That tdr fix probably has nothing to do with the current problem because it is 7 years old, but I managed to find this thread
https://www.reddit.com/r/firefox/comments/7e9l3p/firefox_quantum_keeps_crashing_nvidia_display/
No real solution there, but it seems that I am not the only one with the problem, so at least it is a relief that most likely at least I don't have a bad graphics card like one of the nvidia support agents suggested.