I do think if you were ok with the rog 2 screen, rog 3 screen is better. Rog 2 screen I remember has small grainy issue too at lowest brightness, and I do feel rog 3 screen does not have that.
Also everyday use the black crush issue isn't really an issue, in order to see it I had to turn all lights off in a completely dark room and turn on lowest brightness to really see it.
Ppl want the most perfect screen bec they pay money for it, but I think for our use case we should be fine, so you don't need to be too worry about it.
