Here is the log file after I loaded up the sim, spawned at the bespoke airport (EGGD) and closed the sim again. It still loads the default afcad even though it is installed in the community folder
This is likely the reason:
File \\?\E:\Programme\Microsoft Flight Simulator\Community\EGGD\scenery\PilotPlus\PPEGGD\PP-EGGD-objects.bgl skipped, likely too big to be an airport
Assuming this is the airport ( the other is the modellib, so it's almost sure it's not the airport ), how big it is ? By default, GSX will skip .BGL files larger than 4MB, because usually the airport data is smaller, but some developers might combine other objects in it, so it became larger than this. Skipping files larger than a certain size because they are not surely airports, is done to speed up startup time.
You can change this value by adding this on a new line in the Couatl_MSFS.INI ( after the log line )
airportCacheMaxBGLSizeBytes = 10000000
This will scan files up to 10MB, I don't know how big that file is, this number should be larger, and it's in bytes.