I'm having this issue too. My s9+ flickered green for about a day. It then had dark grey panels horizontally across the entire screen. Then the next day it flickered heaps, went completely green, then went completely black. Now it's stuck black, can't see anything. But it keeps making notification sounds. Don't know what to do?? The whole soft reset, reboot thing, with the volume down and power button does nothing! That doesn't fix this issue
I have just run into this exact same issue which started popping up some time ago with less severity and would apparently resolve itself every time. Now it's gone completely haywire and would only display the screen properly (with a green/grayish tint) at 30% or 100% (no in-between). I was hoping it was only a software problem that could be resolved but after trying a screen record of the problem, the video shows that internally there are no issues and the glitch is a hardware problem. So I suppose screen replacement is the only solution. (Mine is a Samsung S9, 3rd year)
Same problem here. Seems like changing the screen is the only way. But I decided not to get Samsung as replacement anymore. Can't stand with their quality. Bye bye Samsung.