A success rate of 50:50 suggests no causality whatsoever, just simple random chance.
Agree but comming from a 90% CTD ratio even this is already a success and huge step forward. 
Maybe I was wrong with my initial account and I had 99.999% to get a CTD.
All servers and services running as expected 
If you feel better you can change this to every second attempt was successfull.
It is realy sad to declare this already a success
EDIT:
I got a message today that the marketplace content will now be transfered and I should restart the sim. Ofcourse it did CTD. Since then I am unable to get into it anymore.
All the hacks I did try do not work anymore.
I have now more than 50h of “playtime” according to the xbox app, with about 1h of recorded flight time.
I just give up. I guess I will surrender to MS/Asobo, Telekom or who ever is causing these issues.
Looks like my whole setup is just not capable of running the sim. 