Or start VR before the flight completely has loaded, so you see the loading screen in VR. Then you perhaps do not have to do what is mentioned in this post.
and change pre-rendered frames to 1:
Both helped me a lot.
It also could be that you have perhaps dialed in a too high resolution in MSFS, try lowering it in the inGame Render Resolution to lower %. There must be a bug somewhere (or connected to the pre-rendered frames) that if you reach 100% GPU usage, it sometimes breaks down and does not recover for itself. If this happens you can only dial down inGame Resolution, press Ctrl-Alt-Del and immediately after getting a black vr screen pressing ESC. Then it can recover. But after i changed to only 1 pre-rendered Frame i had to do this not very often again.