Issue: when waking the phone there's a ~85+ chance for the screen to not respond to touch. Nothing done in that state fixes it, except for locking it and hoping it doesn't happen next time.
I can't find a pattern to this. Sometimes it works on the third try, sometimes I have to lock and relock for several minutes for it to fix itself. When it unfreezes it does tend to not freeze/unfreeze faster for a short while afterwards (although this is not always the case).
It almost always happens specifically when waking the phone (2-3 times it happened randomly VS hundreds of times it happened on wake)

The only thing that changed recently-ish before the first appearance was me installing Greenify app (and even then it took weeks for the issue to start appearing) Neither safe mode nor a factory reset solved the issue.

The phone is still responsive to any other inputs when the screen is frozen and generally seems normal.

 

In my defence, I bought mine in mid 2016, so it's "only" its 4th year of use.

 

Can a hardware fault depend so much on the phone wake (which I believe is a software-only process)?

 

Already tried that, unfortunately, no change.