I'm sorry, but we cannot help you with that. KLAX requires GSX Level 2 and won't work without it, not just for jetways, but for docking systems and marshallers too.
Main reason I don't want it is because its causing problems with my other addon scenery Flightbeam KIAD, KDEN, KSFOHD and Taxi2gate KSEA.
None of these "problems" are of course caused by GSX, but only your own lack of understanding how it works.
It keeps addint that .pye files into gsx folder
If you are referring to the files in the GSX\airports folders, these are NOT adding ANYTHING visually to the scenery. They are only there for GSX to know how to name ( on its one menu ) some gates, but nothing of the scenery itself will change.
and I have duplicated Jetways at those airports
That's because YOU have either made or downloaded a GSX profile for these sceneries so, you cannot fault GSX for something you ask it do to.
If you don't want to use GSX jetways on a 3rd party airport, just remove the GSX .INI file from your %APPDATA%\Virtuali\GSX for that airport.