GSX cannot possibly have any effect on joystick or other controls so, whatever is happening, is not caused by GSX.
Maybe you ( or another add-on ) is setting a wrong compatibility mode for the simulator, which explains both why GSX goes in Trial and why ( unrelated to GSX ) controls are not working, since it's likely using a different set of preference files, which is what happens when setting a wrong Compatibility mode, like XP or Windows 7 under Windows 10, etc.