I started having the same issues with SU11.
MS Store version of MSFS starts up fine on PC, then try to select something and go fly, and it hangs on the flight loading screen.
I went through dozens of mods disabling them one at a time to find the issue, but it’s completely random.
If I disable all the mods, that seems to work. I guess I’ll have to run without any mods for the next few months.