Lets get you set up for xbox (2020)

This isn't actually CTD but just as stressful to my 83 yr-old brain.  I have been enjoying MS2020  for five years. I got a new PC, connected to Steam and seamlessly continued flying around. The one day I got the above "lets get you set up..." message and ended up losing all my original setup preferences. I couldn't find any way of restoring the originals and managed to rig up a poor substitute.  Yesterday it appeared to download World Update 21 but the key-mappings were all haywire, even after restarting. I tried copying all the appdata/roaming files from my old PC. Steam then forced me to get a 111Gb update and now all my world updates are showing "owned" but not installed. 

I could live with reinstalling these updates, but when I change my key-mappings (and save) the changes are not implemented. Very frustrating. Is there a way to fix this?  Or will I need to uninstall then reinstall?