Just an FYI - I plumped for W11 early December. It seemed OK at first but gradually I began to experience anomalies with various other programs. Then one day FSXSE had a licensing issue which caused the sim to crash after about 1 - 2 minutes and could not be fixed by a reinstall. SO I went back to W10 on 3 January. I went with the well known method of using a USB stick but I foolishly did not unhook my Western Digital MYDrives ( I have 4 ) the result being that the install of W10 used one of those drives as a cache ( for want of a better word ). Which included a Format and wiping out of a bunch of files. Fortunately I had them all backed up elsewhere. So as I said at the start, just an FYI. 1) Unhook everything 2) Don't set things in motion and leave the room. So the upshot, 3 weeks later all is back up and running nicely. One day W11 possibly, but not quite yet. Oh and FSX still gets the licence issue (it seems Steam has to update it) but the sim runs fine.
After some time, I came back to my older computer still running under WIN 7 AND: All my beloved "Thuskas" PT Tu-154B2 and Tu-154M (even in their latest versions) work flawless even the RSBN navigation systems with my addon stations work. So, all friends who like the Soviet airliners are better off not to change to WIN 10 or 11.