Chosen Solution
I have replaced a screen on my iPhone 7 plus two times now with the same issue. I purchased the screens from ifixit, and after installation it would work fine… for a short amount of time… then it would start to lose function in random areas of the screen. If I did a hard reset it would come back in that area but be lost in another. I RMA’d the first one but now the second one is doing it as well. I have a basic plastic case on it and no screen protector. Any ideas?
Sounds like another faulty screen. I would get in contact with iFixit and try sort it through them. Otherwise, it may be a good idea to source one from a different supplier