Try a Forced Restart. The purpose of this is to power off and on the device and refresh the system and files, and delete any corrupt ones which could be causing this.
- Press and quickly release the Volume Up Button
- Press and quickly release the Volume Down Button
- Press and hold the Side Button until you see the Apple Logo
If that doesn’t work, this has indicated this is a hardware issue, likely with the screen digitizer, in which you need a replacement and service at your nearest Apple Store Genius Bar or Apple Authorized Service Provider.
Genius Bar Reservation and Apple Support Options - Apple