I can't believe the number of errors and problems that GSX is having
It surely doesn't.
, literally GSX won't get the correct AFCAD for any scenery at all now
That's because your simulator install is likely full of scenery conflicts.
and if it does, it gets the default AFCAD
Which confirms the above suspicion.
and takes 200 seconds to regenerate the airport cache
That's because you haven't configured the antivirus to exclude the simulator folder, and/or the folders where you have your sceneries installed, so you are ALREADY slowing down your sim just because of that, and GSX is only made this apparent.
It shouldn't take more than 5-10 seconds to regenerate the cache, and surely less than 30 with an insanely high number of sceneries installed.
to end up not doing anything and having the same AFCAD loaded.
As I've said, GSX is only showing a problem you already had, which are conflicting sceneries.
Of course, it's possible to check this, and if you enable logging in the Troubleshooting section of the GSX Settings page and recreate the airport cache, the %APPDATA%\Virtuali\Couatl.LOG file which will be generated, will likely tell you why the airports files might have been rejected, which can be due to a number of reasons, like conflicting files, corrupted .BGLs, too big .BGL.s, etc.
It's always best to dig into the REAL cause of the problems, before saying GSX "is bugged", because most of the time, it's only doing an useful service of pointing you out to a problem you already had in your install, which you might never know otherwise.
So, do the troubleshooting, and report back.