Given the steps ready attempted, you should consider restoring the iPad to factory settings - for which you will require a Windows 10/11 PC (with iTunes for Windows installed) or a Mac computer (with iTunes or Finder - as appropriate for the installed version of macOS).
Download and use iTunes for Windows – Apple Support
Update to the latest version of iTunes – Apple Support
Restoring the iPad to factory settings will completely erase the iPad - and totally (re)install a fresh copy of iPadOS 16.3:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
After the restore, you should set-up the iPad as new from the initial “hello” screen. At this point, do not restore from your iCloud or iTunes backup - as the object is to prove the iPad hardware to be fully functional. If all is well, you can then restore your data and settings from your backup should you wish to do so:
Restore all content to iPad from a backup - Apple Support
If the factory restore fails to resolve the problem, you would be best advised to seek assistance from the technicians at the Genius Bar or your local Apple Store or Apple Authorised Service Provider (AASP):
Genius Bar Reservation and Apple Support Options - Apple