How Could This Even Happen?

That was it, MSFS was deleted by zombies.

The sim is actually installed under Windows Apps directory, which is under the Programs directory, I think. Something like:
C:/Programs/Windows Apps/Microsoft Flight Simulator… Etc.

You may not have permissions to enter Windows Apps path.

The only weird I experienced was a full update in an entire different path from where is was originally installed. I had the main sim (Program code) on my C drive and the content on D drive. That weird install put everything on D drive, under a long path that caused errors for a mod because the long directories/file length was too long for the system maximum file length.

Regards.