This is a strange on and I cant seem to find any similar problems anywhere. Sometimes when I click the VR button in FS2020 the display in the headset (and on the TV mirror) is greyed out, not black but very dull, almost like the backlight isn't working, the colour is all there but just dulled out. The none VR display on the TV is perfect so its only in VR its happening.
If I come out of VR and the headset reverts back to the home screen then that is fine and bright so its not the actual headset that is causing it. It happened a few months ago but seemed to sort itself out but its now returned and does it probably 50% of the time, it doesn't seem to matter what sort of aircraft or location you choose it just seems to be random.