So from what I understand you‘ll have to correct those paths in the user configs you get online (for example flightsim.to) so it finds the correct AFCAD.
The name of the .BGL used to customize the scenery is listed in the [GENERAL] section of the GSX .INI profile. It will include the complete path valid for your system but, don’t worry, there’s no need to edit it out before sharing your work, since GSX will only use the .BGL filename, and will ignore the full path altogether, it has been designed like this exactly to facilitate sharing of GSX .INI profiles without worrying about different paths. As long the currently active .BGL matches the name referenced in the .INI file, the .INI will be loaded by GSX, no matter the path.
Okay, that's what I knew from P3D, I was just confused since most of the authors on flightsim.to advise to change the path.Also, some comments on those files state that it only worked after they did change the path(s).