You've got two separate problems here. One's pretty basic to the hobby, and the other is a little more specific to you and the group you're with. Let's break them down.

Name your approach

DM: "Tell me the skill you're using, then roll."

This is an increasingly common DM interaction. In the old days, the DM was encouraged to simply say "make a perception check to spot the ambush" Or "make an acrobatics check to dance across the room." The player would provide any narrative first, and the DM would do all the math and spit out a roll to make for them.

As the number of skills in some systems exploded, and the overlap between skills increased, this fell out of favor. Allowing the DM to focus on the broad challenge while the players control the flavor of their characters is seen as a benefit.

This has two versions:

• Defining the specifics and flavor of what you're doing. You said you're figuring out the bird, but is it a quick glance (Perception), or a meticulous going-over (Investigation)? Or are you trying to be an academic and bring your book-knowledge into play? Or mutter a bunch of arcane phrases and read the ley lines (Arcana)? Or figure out what kind of natural phenomena could do this (Nature)?

  "I figure it out" is so bland, it doesn't even count as role playing. Give your DM some details, pick a skill to roll, and give them something to work with for pity's sake.

• Everything is a nail. The min-max version of this is picking your highest skill, and finding a way to twist logic beyond all reason until the DM capitulates and lets you roll that skill.

  "I use intimidate. I'm so damn imposing, either the bird gives in or whatever put it there does. Maybe a passing god or nature spirit is frightened by the sheer focus of my concentrated rage. Plus 16, gives me a 34... That's in the legendary range! Gotta get me something, right?"

But to be honest, unless someone very specifically asked you to do this, I would not assume that this is what a DM was going for. You see this coming from players from time to time, but it is very rare for this to be a table expectation (even at relatively optimized tables).

The optimum action

The second problem is how much "slop" a group is willing to accept in the name of role playing. At the end of the day, the only true answer to this is to talk to the group, throw out some examples, and work out the boundaries.

Because here's the deal... Everyone's on a spectrum, and everyone's going to be different.

I wouldn't want to be a player at a table where I felt like my only actions were move and attack (it's not a board game!). On the other hand, I would be very frustrated if the group failed a major objective because a player caught My Guy Syndrome and went PvP because someone touched a minor cursed object (I thought we were all competent adventurers here?).

Some people love the stuff you love. Find that group, and have fun.

That said... Always remember that there's a lot of roleplaying that can happen in the description of your actions, the words your character speaks, and the thoughts they have (which can be narrated out loud).

Just because your character doesn't take an action to make a strength check to struggle to rise doesn't mean you can't describe them struggling to get up.

And just because your character doesn't attack a teammate who grabbed a cursed item, doesn't mean that they can't curse, tighten their grip on their firearm, and call for them to cast it away.

You can forgo optimization or ask your DM to help you out

At least in D&D 5e that you tagged the question for, you shouldn't have that problem, because the DM shouldn't ask you that. The rules advise that the DM should determine what skill might be appropriate to do what you describe you want to do, p. 27, DMG, addressing the DM:

You decide when a player makes a D20 Test based on what the character is trying to do. Players shouldn't just roll ability checks without context; they should tell you what their characters are tring to achieve, and make ability checks only if you ask them to.
Which Ability Does the Test Use? Think about which ability has the most influence on a character's chance to succeed on the ability check or saving throw. [...] Also consider whether a skill or tool proficiency might apply to an ability check.

So, instead of

me: "Uh... I try to figure out what's up with that."

DM: "Tell me the skill you're using, then roll."

This should go something like

me: "Uh... I try to figure out what's up with that."

DM: "You examine the bird. Make an Intelligence (Nature) or Intelligence (Arcana) check."

So, the first way to deal with this is to check with the DM if they would be willing to do it like the game recommends, at least in your case. That way, you will not have to check for optimal solutions. You may end up having to use a skill that you are not as strong in or not proficient in than in some skill that you are and that plays to your strengths, but if the situation is like that, then that is just that.

But what if they don't do this?

It is a real possibility that the DM is not going to be able to easily change their ways -- they may be used to play this way, and maybe the entire group is used to do it like that, and the other players prefer it like that.

In this case, the simple answer is that you can avoid going out of character by just avoiding going for optimized results. Pick whatever skill you think you would be using, and use that, even if you then find out that you are not really proficient in it, and it results in a lower statistical probability to succeed. If optimizing and staying in the fiction do not work at the same time for you, you need to pick one, and it does not have to be optimizing.

Now, in some groups the social norm may make this difficult -- in my group, players sometimes have the tendency to criticise other players that make "stupid" moves, moves that are not maximizing game mechanics chances of success. But my experience is that this is not an enjoyable way to play. Nobody likes to be criticised by their friends, and it also is a very metagamey approach that tends to focus attention on mechanics over imagination of being in a fantastic situation. So if that is your issue, the best way to overcome this that we have found is to talk about this off the table, outside a session, and see if you all can get commitment to be more open and accepting about each players agency for what their character is doing, and about play decisions that are focused more on staying in the fantasy than on winning mechanically.

In my experience, if you can do this, it makes for a much more enjoyable and memorable game. Sometimes it is exactly the suboptimal action, that makes for a moment of mirth or a memorable development. Your DM can also help with this, by awarding Heroic Inspiration for roleplay that ignores mechanical considerations, which can help a lot to offset the mechanical downside.

You have 2 problems you have control over; being a rogue, and not knowing your character well enough

There are things you can push onto your DM or other players in order to help you, but I prefer to take the approach of relying only on people you can rely on, namely yourself. If you ask your DM to change their approach you risk damaging their fun or making them do work they don't want to do. I always dislike those answers.

So I am approaching this purely from a 'what you can do to help yourself' perspective.

Problem 1: Being a rogue

You have found one of the issues with the mechanics of the rogue class. It isn't really anything related to your subclass, its just that when in combat rogues have one trick, and that trick is sneak attack.

To trigger sneak attack, you need advantage or being unseen. There are a few ways to get advantage, but most rely on others, the main thing a rogue can do is to be unseen, which means hiding.

So you spend your turns hiding then attacking, or attacking then hiding. And this is where you are now.

Personally I find this deeply unsatisfying, and while there are things other than this loop that can be done, it relies on combats where there are objectives other than killing, and that relies on your DM creating those situations and in my experience they are few and far between.

To me a rogue is a class for someone who doesn't want to put too much thought into combat, because it has so few option. That isn't bad design, its just not designed for me, and maybe not for you.

Solution 1

Frankly I think being a rogue just isn't for you, you clearly want to put more thought into your combat options, which means you need a class that gives you more things to do.

The answer there is to speak to your DM, retire your character, and create a different character which will be satisfying to you. I always say that means a spellcaster of some kind, but while I think I know what you find unsatisfying, I don't know enough about what you find satisfying to make a real recommendation.

If you like the soul knife theme, a shadow bard (its a 2014 option but will work well enough) doesn't hit quite as hard, but stays on theme, has way more combat options, and can do pretty much everything else a rogue can do as well. If your DM has built a place in their world for you based on your backstory, you can even keep the same character, just swap the mechanics out so no story is broken.

Problem 2: Not knowing your character

When you truly learn a character you stop needing to think about what skills you use, because you know what your character would do. In real life people tend to do what they are good at, and in D&D your character would probably be the same.

When I create a character I ask myself why I have certain skills, and how that influences how my character plays. This means that when I encounter a frozen bird I know what my character would do. Maybe I would try and smash it, maybe I would want to know what type of bird, maybe I would quickly look around in case it is a distraction, maybe I would just ignore it, but either way I would make that choice based on the skills I knew I had because that is how I designed my character, and I wouldn't need to look at my character sheet do make that choice.

Solution 2

My recommendation is that when you create your new character, you really put some thought into why you have certain skills, how you acquired them, what situations you use them in, and how they drive your personality, or how your personality drove those choices.

So you get asked what skill you want to use, and you immediately know your character's main goal is to understand what type of creature this is, so you say you want to make a nature check to recognise it. That isn't looking for your nature bonus, that is you knowing your character cares about this kind of thing. You check your nature bonus AFTER you have made the in character choice, but you make the in character choice because at creation you decided your character likes to know about nature, and thus took nature proficiency.

If you out of character are wanting to know what kind of bird it is, but your character doesn't have nature proficiency, then you are conflicting your RP (there is no wrong way to RP, but to me this is wrong) because every bird is strange to a character that knows nothing about birds, so in character you would have no reason to be thinking about the type of bird. And if in character you did want to know about types of birds, you would express that via nature proficiency, or at least training in nature (like a downtime thing, or learning from a companion etc) rather than just as the question because the DM drops a situation on you.

I have had characters walk right past something my Dm drops on me because in character I don't care about it. Out of character I hope someone bites, but I don't get my character to do something against their design just to ensure I bite the hook the DM lays out.

Assuming it is much easier to change your own behaviour than the DM's:

me: "Uh... I try to figure out what's up with that."

When I describe the actions of my character at the table, I have the mindset that I explain visible, clearly understandable actions of the character. I view myself as a camera, or something like a TV moderator narrating the activities of my character. In this example, it means I wouldn't say "I try" or "figure out". These are very vague terms, and the other characters do not see my character "trying", they see him "doing" something. I would say something like "I go to the frozen bird. I'll take some stick or my utility knife and prod the bird a bit, looking for what could have caused its death. Do I find obvious wounds or other weird stuff?"

This has some benefits:

• It is more or less entertaining for everybody at the table.
• It clearly communicates what the character actually does.
• It is fluid and does not waste time with back-and-forth communication ("I try to find a stick" ... "DM: ok, you found one" ... "I go to the bird" ... "DM: ...ok..." ... "I prod the bird" ... "DM: oook?" ...).
• It doesn't require to say "I try". Standing up and prodding the bird is not something that can possible be hard for my char if nothing unexpected happens. Even if I spill all of those sentences out before the DM can interrupt me, the DM can still say something like "OK. You walk to the bird, and just as you pull out your stick, an ugly goblin jumps out from behind the rock next to the bird and catches you - the bird seems to have been a trap." or whatever it may be. I.e., even if I say something that then does not happen, it is easy for the DM to correct that on the spot.

The second issue is this:

DM: "Tell me the skill you're using, then roll."

They should not ask you that. They should specify a skill, or maybe a choice between two skills depending on the situation.

But the root cause of the issue here is that your original line did not give the DM any information about how you are "trying to figure something out". They should be telling you "OK, how are you doing that" (which is a hint that they expect a description like given in the first part of this answer). You cannot force them to do so, and even a good DM can always slip in the heat of the moment. So feel free to interpret their question like if they had said "How are you doing that". Don't just tell them the skill you picked and roll it, but while you get our your dice give a detailed description (like in the first part of the answer). Then, if the DM still does not tell you which skill you should roll, you can either pick one ("How about Investigation?") or ask them to make a choice ("Do you wish me to roll Investigation, Medicine or Nature?").

And on the question of How to do this (i.e., how to keep this stuff in mind): hard to tell. I find it rather easy to keep two realities in my brain, both relatively strong in the foreground, when roleplaying. I.e. the reality of my character, and the real reality. If that is an issue for you, I would err on the side of concentrating more on the character's universe. It is better for the session to err on the side of "too much in-game" than "too much out-of-game". If that is difficult for you, think about it like method-acting. Try to feel or visualize strongly whatever it is your character may feel or see.

Basically, I would try to stay in the in-character mindset 100% of the time, until something at the table (i.e., the DM) forces me out of it. As long as I can imagine what situation my char is in, and as long as I have his character traits in the back of my mind, this seems to flow rather naturally. If that is an issue for you, this might be a different question though.

Your most optimal solution and your in-character solution do not necessarily have to be mutually exclusive, although as you've clearly experienced, it can be challenging to see your way through to a narrative that makes sense.

There are two types of metagaming; the kind that is necessary to play a game with rules, and the kind that attempts to subvert the rules and spirit of the game. Looking for the best thing your character can do isn't trying to subvert the rules or trying to take advantage of out of game knowledge - your character should, after all, know what they're best at. But the rules require your voice for them to act on it, so you have to figure that part out, too.

This mostly sounds like an issue of perspective, where you feel because you're looking at the mechanical numbers you are no longer acting as your character but as a player; however, this behavior is not against the spirit of the game, and is in fact somewhat by design, else there would be no numbers or dice rolls at all, it would just be an improv session (which there's nothing wrong with, mind you.)

Consider, for a moment, that in a tense situation during an adventure, possibly a matter of life or death, that while a way to make one skill fit every situation is generally close to impossible without some very high die rolls and some suspension of disbelief, it is absolutely within the character's best interest, from their perspective, to do the thing they are best at when their life or their friends' lives are on the line.

Of course, there are plenty of moments where some IC 'flexing' and showing off is okay - but generally, if you're a fighter and some big burly is stomping all over the squishy casters, no one wants you to roll a persuasion check to convince everyone to have friends- they want you to crack a skull or grapple the big guy away from the squishies - not just because it's the optimal thing to do, but because their characters don't want to die.

If you approach the scenario with that perspective in mind, it sort of becomes ideal and very much in-character to look for the optimal option.

This varies table by table

Even when playing within the same system, the exact methodologies vary from one table to another. This one can vary significantly.

Some GMs will simply tell you what roll to make. Others will ask you how you want to go about it and then ask for justification if it is a truly surprising method, and then let you roll. Occasionally, you will find GMs that want to make most of the rolls themselves.

I think the second one is slightly more common and as a player I prefer it because it means I get to influence the roll and I get to pick the most favorable approach I can reasonably justify.

But you will see all of these. I don't think any one of them is fundamentally better than the other in most systems. (Though it can occasionally be a big deal for say Lunar Exalted that want to very specifically justify the attribute(s) used to invoke excellencies, but that's a bit niche).

I bring this up as background because the fact there are multiple approaches and that none of them is wrong is relevant to possible resolutions.

You can either ask your GM to accommodate your preference or adjust your approach to accommodate what your GM already does

Fundamentally, you are having a clash of preferred play approaches with your GM. There are really three ways to address this.

The first, especially if others at the table share your approach, is to respectfully and politely ask your GM to shift their approach to be closer to yours. Say something like, "I'm not used to selecting which skill to use and I find it unpleasant and immersion breaking. Would you be willing to more often tell me what roll to make?"

Notably while this first recommendation works best if other players agree with you, it can still work with an accommodating GM even if you are the only one with this preference. This isn't a mechanical difference or something that will give one player an advantage over others. It does require an accommodating GM, but it is perfectly possible for a GM to tell one player what rolls to make while expecting the others to tell the GM what rolls they want to make.

While not exactly the same thing, I remember when I was quite young and my older cousin was introducing me to role-playing that there were times he would quite directly suggest what I should do while letting his (older than me) friends decide without suggestions. Its obviously not the same, but an accommodating GM could do this when it comes to what to roll.

The second is to adjust yourself to this approach. To a large degree, I think this will come naturally with time playing at the table. But you can speed up the adjustment process by making yourself very familiar with your character so you know what the most optimal approach is without looking most of the time. You can also let role-play lead and decide based on what your character would do without regard for the numbers, though this does risk my-guy syndrome if your party is hurt by you deliberately making sub-optimal choices.

The third is to find a table that better fits with your personal preferences.

Addressing more varied combat strategies

Combat in D&D for some classes can be a little repetitive. While exceptions exist, many builds of warlock will find themselves saying something along the lines of "I cast eldritch blast" a lot for instance.

For many players, this may not be a problem at all. If this bothers you, then there are a few options.

1. Even if it is mechanically the same, you can provide different descriptions for your actions. Instead of just "I cast eldritch blast" you could say, "I draw upon the powers of my infernal patron to blast the orc" and roll for eldritch blast. Or "I channel hell itself". You can change the descriptions for the same mechanical actions quite a bit even if the mechanics are mostly the same. In some systems this goes by something like "stunting" and might have some mechanical implications, but in D&D it is just adding flavor.

2. You can specifically look for opportunities to do something more than your usual. You will still be using your tried and true main tactic often, but you can make a point of changing it up as often as the tactics permit. This is made easier if your GM is providing varied tactical situations with varied terrain. Also, depending on your table, you may be able to suggest the existence of favorable terrain or environmental tools you can use. You can ask if there is a chandelier to swing from or if there is something explosive handy, as long as your GM is cooperative for that sort of thing.

3. You may want to change class. This particular issue is present for essentially every D&D class, but some are more affected than others. A rogue stereotypically wants to sneak attack as often as possible, and that will hold true for many rogue builds. While there are many builds available, a stereotypical warlock can expect to use eldritch blast a lot. But classes that focus primarily on casting like the Wizard inherently have a bit more variety if only because they have a larger variety of spells and might even run out of the slots for the spell that would otherwise be the tactically smartest.

There are a lot of great answers here. I'll add a few things.

Summary

Role-play.

Don't say you're figuring things out. Say how you're figuring things out.

Don't be mechanically optimal in combat. Be strategically optimal.

Details

"Tell me the skill you're using"

The DM may think he is doing you a favor and may also be trying to speed things along here.

The long-hand version involves you describing what you're doing, the DM asking for a skill check, potentially with the player requesting a different skill. This happens so often DMs will often short-cut the process by having the player pick the skill.

Alternatively, the DM is stuck with "I try to figure out", and then the DM says, "how do you figure it out", and then the player says something and back and forth. Very slow.

YOU can help keep things moving a lot by avoiding the mechanical intrusion in the first place.

Don't say "I try to figure out what's up with that", say something relevant to the skill you want to use.

• "I'll take a close look at the bird. Do I see anything significant?"
• "I look around the room. Are there any clues?"
• "I examine the bird. Is there any obvious sign of magical damage?"

Then the DM can say, make a perception, investigation, arcana check, or whatever, OR the DM can say roll what check you want, knowing that you're justifying it.

Psychic Blade Sneak Attack

IS the psychic blade sneak attack the best mechanical option? IF SO, DO IT. IF it's the best mechanical option it's likely the best roleplaying option. You're in a life-and-death fight, if shooting them from behind the wagon is best, then do it.

But it shouldn't be the best

. . . at least against smart enemies.

Smart monsters should be fighting to win, or get away, or whatever their objective it. If the freaking psychic weirdo over there is plunking away with those psychic knives, send someone with great observation over there the long way to sneak up on the sneaker.

For that matter, their fighter (or whatever) can still run right up and hit you. You're HIDDEN, you're not unfindable. Someone can still hit you, they just have to attack with disadvantage.

So, repeated hide/sneak attack should not always be the optimal attack.

ALSO, your character is also in a life-and-death fight. Act like it. Take a cue from movies. Sometimes staying hidden and plinking away is the best course of action, sometimes it isn't. Sometimes the hider takes the opportunity to move somewhere else and hide, because the other side is trying to kill them, and hiding in one spot too long is not smart.

So again, YOU can help keep things moving a lot by avoiding the mechanical intrusion in the first place.

Put yourself in your character's shoes. Role-play in other words. Does that spot over there look like a better hiding place? Then move. Don't wait for the DM. Assume the monsters are out to get you.