If you haven’t, I certainly would enter a support request.
Here are a couple more to try.
RESET THE MSStore INSTALLER
- Bring up Task Manager (CTRL + SHIFT + ESCAPE)
- Select the Services Tab
- Find the Microsoft Store Installer
- Right-click it and select Restart
and this:
- Go to the default installation folder:
C:\Users\User_name\AppData\Local\Packages\Microsoft.WindowsStore_8wekyb3d8bbwe\LocalCache
- Manually delete the files
- Reboot your PC and try to install or update Microsoft Flight Simulator again.