red screen

Hello,

I am just trying to figure out whether the artifacts I'm sometimes seeing on the screen are a result of a hardware or software issue. Using 2017 MBP 15 inch.

This is the screen I get when trying to play some games in fullscreen mode. When I switch to windowed mode, the problem goes away. It happens mostly in Steam versions of some Telltale games (Sam & Max season 2, Tales of Monkey Island, ...)

I sometimes saw the same red color but in smaler patches when I was using Finder in CoverFlow mode and went through a lot of photos. the coverFlow part just started flickering in this red color.

Also I have artefacts like this time to time:

https://www.youtube.com/watch?v=-wOs6Nluaxs

So any suggestions on what to do? I reset SMC and NVRAM, I reinstalled HighSierra (even though not a clean install with reformatted hard drives). Is anyone else getting these problems, is it normal, some kind of a software issue or what the **** is it? There is no apple store nearby, so I'm trying to self-diagnose and try. to get a repair if I know it really is hardware.

Anyone else getting these issues with Telltale games?

Thanks for the help!