Have you reset your iPad to its factory default condition to test it out that way? If not, then follow the instructions below.
First you should use your iTunes program to do your backups. Be sure to know how the backups work and what is included and what is not. This is a key point for having a successful outcome. Then, when you run the iTunes program on your computer to set up the factory default condition on your iPad, make sure your computer anti-virus programs are turned off, for the time being.
Then at this particular time do not restore your backup, so you can test out your iPad in its factory restored and pristine condition, and note if any problems remain. If any do, then "these" are the ones to take to Apple Support, if for no other reason than for the software engineers to analyze and figure out what is going on. The fact that you present these engineers with a "factory default iPad" then takes away any possible connection to your apps or your data - which has caused some problems with other users on this forum. You need to remove all possible connections with your own personal usage, in giving the Apple software engineers some clean data to work with.
After all that, then you can restore your backup, and go from there forward with either your Apple Support ticket -or- you may find out that things are working normally again. I've already lost count of HOW MANY USERS here on this forum have come back to me and told me that this solution has solved their problems. And, as it is with "solutions" there is not a "one solution fixes all" situation here. I'm just relaying to you one solution that has had a whole lot of success here.
The first few links below are about your backups ... and so make sure you understand them sufficiently. And then the last link is for using your iTunes program to reset your iPad to its factory default condition ...