Buy from ms store?

Yes

Run windows update and click “check for updates”.

Updates an issue that might redirect you to the Microsoft Store page for Gaming Services when you try to install or start an Xbox Game Pass game on your Windows 10 device.

Source https://support.microsoft.com/en-us/topic/june-11-2021-kb5004476-os-builds-19041-1055-19042-1055-and-19043-1055-out-of-band-e12f58c7-4ceb-4d24-adfb-b13820f4e86b

edit

Smth important about steam
https://forums.flightsimulator.com/t/ok-so-why-has-my-msfs-deleted-itself/304797

https://forums.flightsimulator.com/t/stutters-low-fps-and-lost-path/408034/17