I have the exact same issue. I have a Ryzen 7 3700 X (stock), 32 GB RAM, Radeon RX 5700 XT (slightly undervolted). Sometimes I can play for 10 minutes, sometimes 40 minutes then all of a a sudden green screen on the screen with HDMI then PC reboots. I monitor the temps and they are normal, GPU idling at 60-65 C, CPU at 55-60 C.
No other game or app is doing this. I can play hours of Division 2, F1 2019, Gears 5 and so on. MSFS is the only game that is crashing my PC. I've just spend a lot of money upgrading to this new setup but cannot enjoy the sim cause I know it will crash.
I've also tried everything from increasing the virtual memory, deleting logitech software, running the GPU at default, disabling v-sync, re-installing the game and so on but nothing seems to work.
Is someone at ASOBO or MS reading this? I hope they will so that this issue is getting sorted out!