A forced-restart may be helpful - as this will often clear an isolated software or performance issue:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

Otherwise, you may need to perform a factory restore:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Before doing so, ensure that you have an iCloud or iTunes backup of your iPad - as this will be needed to restore your files/data and settings:
How to back up your iPhone, iPad, and iPod touch - Apple Support