iPhone 11 apps jumping on screen
Having to press repeatedly to enter information
iPhone 11 Pro Max, iOS 18
This is potentially a sign that the screen is beginning to fail.
Try a Forced Restart to see if that might provide some help. Follow the instructions very carefully, as this is a bit tricky. (Hint.....ignore the "slider" when it appears and keep holding the Side button in until the Apple logo appears. This might take another 30 seconds.)
Force restart iPhone - Apple Support
If no help, make an appointment at the Apple Store or take the phone to an authorized Apple service shop so that they can check and test the phone and go over your options with you.
Genius Bar Reservation and Apple Support Options - Apple