I have the same problem. My Apple Watch Ultra II suddenly went nuts. It started with many message on my iPhone for keyboard input, like when you type your password on Apple TV. Then it was like somebody took over my Watch screen. I saw constant random input of text. After a while the watch got time locked, because of the wrong unlock code. Now I have to wait for 3 hours! before next attempt to unlock. I put the Watch on the charger for now and hope the error is over by next morning.