Hello @ClevaTreva68,
I just launched MSFS on my PC and then Starfield on my Xbox Series X using the same Xbox account. I could play both simultaneously.
What you can’t do is play MSFS in two locations at the same time using the same account. If you launch MSFS on PC and then launch it on Xbox from the same account, you’ll get a warning saying that the account is already in use. It will then ask you where you would like to play (console or PC) and then terminate the other session.
I hope that clears things up for you!
Thanks,
MSFS Team