What is going on with my iPhone?

So I got my iPhone 12 screen replaced two days ago. I think I possibly have a broken digitizer as well, not sure. When I got my phone back the first time, touch was not working. So he replaced the screen again. It worked. Had to factory reset my phone cause of lock out. I live pretty far from an Apple Store so I went to a licensed place. Any ways, yesterday morning I experienced ghost taps. Then nothing. This morning, ghost taps kept going to contacts and then I exited, then ghost tap swiped right and then left and all the way left and went to search and it typed “v”.

Freaked me out so I quickly turned my phone off cause like what? So now I’m here. No ghost taps so far.

Question is, could it be the digitizer or something more sinister?

I kind of regret turning the phone off to see what would’ve been typed.

Thanks in advance!