But the settings menu remained the same as the trial version (not extended).
What do you mean with "Trial" as opposed to "Extended" ? There's no difference in menus when the program is in Trial, the only difference is that it will work only on Trial airport or FSDT airports.
For example: airport logos are not downloaded or converted (downloaded logos are verified and successfully work with other users).
Nothing in GSX downloads logos. And none of these features will change if GSX is in Trial or not or the L2 Expansion is active or not.
And also there is no time adjustment for loading or unloading passengers. (I am using Prepar3D 4.5, operating system of windows
It seems you confused the explanation. If GSX L2 is used, the timings are NOT supposed to be adjustable, because they are dependent on the Passenger Density slider, that's what the manual says. The timings in seconds only appears with basic GSX.