I have been trying to trying to re-install and update MSFS2020 Pro DeLuxe for three weeks.
Had it installed from release day, worked fine, then the patch screwed it.
I have tried all the fixes reported in this thread.
This fault is caused by the application and update delivery mechanism ...IMHO.
The MS Store keeps giving these errors:
0x803FB107
0x80070141
0x80073D12
0x80073D02
0x80073CF9
0x87E00017