For a few versions now, I’ve noticed a consistent behavior. If you end a flight in VR and attempt to load or reload a flight plan in VR, the sim hangs on the loading screen. The only way out is to kill the MSFS application and start again.
Yes, you have to first switch out of VR to see the load screen. You can also recover from it if you didn’t switch by hitting escape (which closes the file open screen that you can’t see)
I just discovered a third option which is to take off your VR heatset and find where the load plan dialog appeared on your desktop and use it from there.