Screen is half responsive and image shaking, what could be wrong?

The screen on my iPhone XS Max has the following symptoms recently:

1. Touch screen is half responsive, which means sometimes fully responsive, but some times not responsive.
2. image “shaking” or flicker, some times, not always.

here is the history of the phone, screen was damaged last December, so, I have it replaced in Jan. this year, (I have it replaced with the aftermarket part, not the OEM one from Apple). It works pretty good so far until those symptoms shown up few days ago. So, what could be wrong, the display becomes bad or the GPU on logic board might be the issue?

Any thoughts?

thanks,