@SmotheryVase665 “saved my life” by linking this [KNOWN ISSUE] ...
Actually in my case I did some chaotic ettempts, but what seems to fixed the issue was either running “Gaming Services Repair Tool for PC” or (most probably) running WSReset.exe
I think the whole thing got broken after I logged into Microsoft Store. Ironically - I wanted to get rid of the annoyting warning in XBox, saying, I’m not logged into MS Store 
Well, I’m glad my settings and history is back.
I usually copy my \WpSystem\S-1-5-21-3641412585-73280727-4270733975-1001\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\ as a backup but in this case it didn’t help.
BTW - I’m thinking about moving to the Steam Version of MSFS, but I wonder if the ussues are the same there - does anyone know?