You can return your iPad settings to their defaults without erasing your content.
If you want to save your settings, View or change cellular data settings on iPad (Wi-Fi + Cellular models).)
When you reset network settings, previously used networks and VPN settings that weren’t installed by a configuration profile or mobile device management (MDM) are removed. Wi-Fi is turned off and then back on, disconnecting you from any network you’re on. The Wi-Fi and Ask to Join Networks settings remain turned on.
To remove VPN settings installed by a configuration profile, go to Settings > General > VPN & Device Management, select the configuration profile, then tap Remove Profile. This also removes other settings and accounts provided by the profile. See Erase iPad using your Mac or Windows device.