Oh wow. Thank you for such a detailed report. Will therefore provide same for comparison (having CTD issues in LSZH stock airport, also reported by multiple other users others CTD on official LSZH - #9 by QuietLawyer4339).
I fly (at least I try) XBOX Series X in 4K 60Hz on LG 4K TV, WiFi 5 connected with router within 20 feet on same floor in direct sight plugged into 300Mb symmetric fiber AT&T. In peripheral terms: I use Turtle Beach Velocity + wired Logitech dumb mouse + standard xbox controller (removed flight surfaces bindings in profile to avoid double axis bindings)
Besides MSFS I have several more games including Elite Dangerous installed, but I keep about 65% of drive space clear. Have never experience CTD in any of those games yet.
All data online is On but multiplayer is disabled as I do not pay for Xbox Live or Pass currently. I use Live traffic and Live weather. All traffic sliders set to 100. Assistance all off except landmarks POI and taxi arrows.
Rolling cash is currently on and 64G size but I tried both with it turned off and freshly cleared too.
Sim reserved data was cleared about a week ago and after that I reinstalled everything step by step, which is Deluxe + Premium + all WUs + BREDOK’s 737 Max + Liveries for 737 + Liveries for A320 Europe + Enhanced Airport Graphics + Airport Jetway Pro by LVFR + some more, but I do not suspect those as had CTD in LSZH from even vanilla state cleared reserved space sim.
Meanwhile, may I kindly ask you @NixonRedgrave to try flying out and around LSZH and see if you experience any CTD. I will per your suspicion try same with AI ATC turned off. In hindsight I can also put it into suspects list as I had it on most of time and CTD happens somewhat at the moments when Live Traffic aircraft would normally communicate with tower regarding me blocking their taxying or takeoff - he he =)