Hi!
I have a 3a, and have a similar issue. Sometimes it wouldn’t even recognise my touch, I uave to tap repeatedly on the screen, then when the screen is on, there is no issue. This happend on hard surfaces, like tables, or even when I held the phone with my other hand.
The issue started after an update (Asteroids-V3.1-250320-2319)
I don’t think it has something to do with the update, but I’m only experiencing this after updating