I hope you don't have the same problem I did. Microsoft apps just completely died for me. I first noticed it with the picture viewer (check if that works for you or check if any other microsoft app will run). I got around that by using a 3rd party viewer but then MSFS wouldn't load and then the Store died.
The rest of my programs all worked fine. It was only the MS apps that wouldn't run.
The only solution for me was to completely reinstall windows 10. Not even an inline update would work so it had to a clean reinstall. Thank god I have my main MSFS folder on a separate drive.