Maybe you have already tried, but since you don't mention it I have to ask: do you face the same problem with all chargers?
I had problems with the general responsiveness of the UI on my Pixel 6a while using a specific charger. I first thought it was a phone problem (hardware or software) but then I realised the buggy behaviour was only happening with this specific charger. So my conclusion was that the charger was to blame, not the phone :)