Holy horse crap batman! I think I got it!
I used DDU before the swap. Also the options.lua was blown away when I nuked the game install and all traces during my troubleshooting. I do appreciate the help though. I was about ready to give up.
Anyway, back to the fix. During my Nth test run today I actually got the editor to hang rather than CTD. This time I had more information in the log file and it crated a crash dump finally. There was some sort of access violation with a amdxx64.dll. On a whim I just tried a previous driver version and it opens the mission fine now. No more screen flashing on map load either.
Why the laptop's Vega56 opens the mission with the latest driver and the desktop's 6800XT does not is beyond me, but I'll take it. I have been at this for well over a week.
Daemoc's post in AMD Adrenalin 22.12.1+ causes Mission Editor to crash was marked as the answer