Basically, yes. It’s trash.
Ordinarily I’d say if you can still manage to navigate your way around the basic functions, then it’s probably just a dead screen in need of replacing…
However, given you said you can’t even get it to respond to your attempts at turning it off (the most basic of functions on a regulated mod), then I’m strongly inclined to agree with @SmilingOgre’s assessment.
As to your other question, topside or… My vote is definitely for the original Dovpo (not the plastic version). Those things are bulletproof IMO.
