Had the same symptoms - namely the graphic card "crashing" under load - on a 2080Ti. Temps were reported as high in OpenHardwareMonitor, but nothing worrying. Turns out the thermal paste had been badly/inconsistently applied on the GPU from factory. Re-applied thermal paste correctly, and the card has been running perfectly ever since. I'm not saying it's the same for you : it can be a lot of other things. But i would never have thought of a thermal paste issue on a new card, and this issue had been bugging me for weeks, and of course it's the last thing I tried.