Patchy6 Also how the green screen reacts to my touch input feels more like a software than a hardware problem. It comes and goes randomly, now I didnt had it for over a week but today it returned. After pressing random on the screen it sometimes vanishes.
If the phone is running the same code each time it draws the lock screen (which it is), and running the same code results in different colors on the screen, that is 100% consistent with a hardware problem. It's not impossible for it to be a software problem, but so far details have not been presented that implicate a software problem.
Probably the best way to collect experimental data is W1zardK1ng's advice earlier in the threat. If 100% of the GrapheneOS software on the phone is replaced by Google's software and the problem is still there, it probably isn't a GrapheneOS software problem, and honestly, given the symptoms presented so far, it probably won't be a Google software problem either.