Hello everyone. for those of you who are trying to install add on scenery (freeware payware anyway anywhere) the default directory is in your program files IF you have installed the game from microsoft store gamepass
after hours of digging, its in a simple folder tree neatly tucked inside the
C:\Program Files\Flight Simulator\Community
paste your add on scenery there and restart your sim. (pc restart wasnt required in my case) and your add on scenery should show up with a star in the map.
hope this helps someone.
keep safe!