I think you’re right that the crashing has to do with resources. Before the UK update, I was able to open and close the WMR menu almost every time from the flight sim main menu. However, since the UK update has made the main menu laggy (especially after zooming in on the UK region on the World Map), I now crash out of VR most of the time when trying to open the WMR menu from the flight sim main menu. The workaround now is to either open VR and the WMR menu prior to setting up your 2D flight, or by opening the WMR menu inside the Cliff house, rather than inside flight sim.
I have a powerful rig so that’s probably not the limitation (10700k, 3080, 64gb ram)