Guys, I think I got it!
It works again (fingers crossed it stays that way)
I tried two things and, silly me, in the end I’m not sure which one actually did the trick.
- I reinstalled the Nvidia driver (with the “reset” option to force a fresh install)
- I also deactivated the steam Cloud backup and deleted the steam local backup since I found I thread that this helped somebody against CTD to restore the sim
Now, since I’m tired and did so many restarts, I unfortunatelly don’t remember if I did thouse things seperatly or together and therefore I’m not sure what actually did the trick. Stupid.
But it was one of thouse two things and it seems (so far) it was not a power related thing.
I will mark this as solution even though I’m not sure which one of these two things actually did the trick.
Thank you all for your help!!