Hi buddy,
Not a problem for me after 1h in MSFS temps are actually very good GPU die in it’s norm 64-68c and GPU vram 74c and this is on RTX 3090 FTW3 v2 then my cpu just hit about 42c @ 5.3ghz I have nice airflow big case and lots of fans, my room is nice vented also so happy with temps not to mention I already do my MSFS in task manager the flightsimulator.exe set in high priority, but setting it or not dose not change anything, my pc nice has nice frames so I’m happy with that 
oh and my GPU core speed always stays at 1950 but always starts for first 15min keeps 2010mhz then drops down by 60mhz which brings me to 1950mhz and I have updated bios on card via EVGA precision X and resizable bar activated, and this is OC bios on the card selector on.