Oops, I forgot to mention that I have another strange problem that might be related.
Sometimes, and exclusively when watching Netflix, my screen freezes and shortly after every pixel of the screen lights up in the predominant color of the picture last seen before the freeze.
Then the sound begins to crackle, slightly first, then increasing, and eventually hold one beeptone after a while.
When it seems, the PC froze completely, everthing goes back to normal, Netflix is paused, but can play again after reloading the site.
The only thing that stays after such an incident is, that the graphics chip, though working again, cannot be identified by any program. Geforce Experience says "unknown device", the analysis tool of the manufacturer just states 0 values all over and even windows device manager doesn't seem to see any kind of video hardware.
Rebooting the PC makes the GPU show up again.
This happens very seldomly and without any tracable pattern. Sometimes nothing happens for weeks. I even had specialists look into it, but nothing was found.
Sometimes this is followed by the windows popup stating " the display driver stopped responding and has recovered." specifying "nvidia windows kernel mode driver" as the culprit.
Well, I guess it always pops up after that, but it depends on how fast the picture recovers wether I can see it before it's gone.