You might want to start the official “readme” publications?
Starting with:
[Read First] VR FAQ - Virtual Reality (VR) - Microsoft Flight Simulator Forums
How to activate VR in MSFS – Microsoft Flight Simulator Support (zendesk.com)
Are you sure you didn’t bind TAB instead of CTRL+TAB to switch to VR for example? You might want to review all your key bindings for anything using TAB Otherwise you can file a bug report (zendesk) and/or VR > Bugs forum.