Isnt it Ctrl-Spacebar ? ( or maybe the default is Ctrl-Tab). Is the Oculus itself working ?
you dont need the virtual desptop to fly in FS.
Fire up your windows in 2D, then just load the Oculus app. (just on your 2D desktop)
go to settings in you Oculus app, and make sure you enable the ‘public’ test channel.
when you do that, a new version of oculus will start installing ( updating). let it finish.
(You just have to do this step the very first time.)
then load MFS 2020. (not from the virtual desktop, but from your 2D windows desktop).
Once your flight is done loading and you are in the cockpit, you can press Ctrl-Spacebar ( or whatever the default is, maybe it is ctrl-tab and i just changed it to ctrl-space, i dont remember now)
After 5 or 6 seconds loading, the view on your 2d monitor should then change to the double images ( as seen in VR). If VR is working/ activated , you will see it on your 2d monitor, ( the double oval images), and you should be in actual VR when you put on your headset.
You will still have to center your view when you get inside the cockpit in VR mode ( it usually positions you in weird, off center locations) .
for me, i set it to middle mouse button . Make sure you look straight ahead in your real room, at your yoke and screen, keep ur head still, and press the VR reset button.
Good luck.
1st make sure you can get into the cockpit in VR, then you will need some additional tweaking to center your view inside the cockpit: -
(for me , i use front, back, left, right arrow to translate the view to center it, and i use + to raise the seat height, minus to lower it.
You will have to program these as keyboard buttons in the options/control menu in FS.
I may be missing a step or two depending on if you have steam or not, but there are youtube videos that can guide you. Its been a while since i set up my VR, and i dont remember if