If your iPad is visibly "glitching" as described, it will have a display hardware fault that will require repair. Hardware faults cannot be resolved by attempting to update your iPad.
You would be best advised to visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad - and you will be able to explore your available repair options:
Genius Bar Reservation and Apple Support Options - Apple
Alternatively, you might consider using Apple's mail-in repair service:
iPad Repair & Service - Apple Support