Well its fixed but what a nightmare of an issue to find information about.
I had heard mention of some joystick XML files that held the joystick data and if this became corrupt then MSFS2020 would crash with out and warning or error msgs on load up (this appeared to be my issue), how ever using the Steam version these files don’t exists as they are only for the MS store version, however I saw a post for some one looking for the Steam joystick files for MSFS2020, and after extensive looking he located them here.
C:\Program Files (x86)\Steam\userdata\23149991\1250410\remote
I backed up the files, and then deleted the contents of the remote folder, started MSFS2020 and it loaded as if I had just purchased the game today, asked me my experience settings, told me it had found all my controllers and loaded the game up fine with all my controllers showing but with clean bindings, rebooted and a steam msg came up saying my new created files were newer than the ones on the steam cloud and did I want to download my old files or replace with my new ones, so I replaced and now all is good.
So the issue was corrupted joystick files, 1 for each controller were corrupted and each time I started Steam it downloaded the corrupt files which brought MSFS2020 to a scream halt CTD>
So if you have the Steam version, back this folder up at least once a week or if you make any changes to joystick bindings just incase your Steam cloud files get corrupt.
C:\Program Files (x86)\Steam\userdata\23149991\1250410\remote
I like to say the people who programs this stuff needs to think a bit more of the end user, if files get corrupt just let the program bin them and take the user back to at least a fresh start, all I did was delete the folder and MSFS2020 started afresh, how hard would that check take to put in place instead of CTD’ing with out and logs