These problems aren't exclusive to MSFS, this is a problem with the Microsoft Store and all of it's related services. The process actually works as it should on Xbox, PC gaming has been an afterthought for Microsoft for what, at least the last 20 years? It's only recently that Microsoft has embraced PC gaming again, which is why they are releasing new titles of their "staple" PC franchises like Flight Simulator and Age of Empires and releasing all of their big exclusives on both PC and Xbox day and date. While the Microsoft Store and Xbox apps have improved in the last few years, especially in the last 12 months or so thanks to Microsoft's push for Gamepass subscriptions on the PC, they are still awful and have been since Windows 10 was released. The Steam version does not have these issues. So it's not so much Flight Simulator as it is the Microsoft Store.