I too started to have this problem after the latest sim update. Launched fine. after a few minutes… all screens lost signal.
Now today I opened task manager to see the temps… I saw that the GPU (Nvidia 3080) spiked at 100% from the load screen. And stayed that way while only showing the splash screen stills. The main menu came up… still 100% GPU usage… temperatures climbing. I usually use this game with Ultra Settings. So to look into this I did jump in before it crashed and tried lowering it to “Low end” profile. Saved and looked… Nnnope. Still rock solid 100% GPU usage. So I tried launching a flight. It now calmed down and came down to something like 30-40%… I set it back to ultra and now it seems to float steady with 55-60% in the menus with the nice hangar background. And GPU-temp of roundabout 60 degrees. But not climbing catastrophically like it did before.
My guess is that something in the update caused a runaway process or memory leak with my old graphics settings and the GPU essentially panicked and shut off. Maybe with others as well. Resetting the settings to low end temporarily and then back up to ultra seems to have fixed the issue for me.
Now… if I could only find out what is spamming my pitch trim…