Is it somehow possible or is an update planned so that you can configure the jetways yourself like in P3D.
The way GSX Jetway replacement is done in GSX is completely different than P3D. There, we had SODE, which allowed to create custom Jetways on the fly, completely bypassing the default Jetway system in the sim.
In MSFS, since there's no SODE, we use the default Jetway system, and provided GSX with a set of replacement files that has been pre-built based on default airports data, so they can't be edited, we can only keep up when MS updates any of the default airports and rebuild the file set for any changed airports and release an update. It's not possible to edit jetways in realtime this way.
I miss that the most. It looks bad at times. Here for example Frankfurt.
You don't say which Frankfurt is that but, assuming you mean the default handcrafted version that comes with MSFS Premium versions, it's normal you would have problems there, since the replacement files for GSX Jetways are based on default airports, not enhanced airports. Sometimes the data is identical, but at EDDF (and other places as well), it's not, so you must Disable it from the GSX Config Panel, exactly as it was any other 3rd party airport.
As the manual explains, Asobo/Microsoft airports are not automatically Disabled when you click the "Exclude 3rd party" button, because each one of them is different, in some cases replacement works fine (because the parking data is the same, only the buildings are better), in other cases it doesn't, so we leave the choice to users. EDDF is surely one that should be Disabled.
We can't supply a set of replacement files for the Premium airports, since those are encrypted, and the current version of the Navdata API doesn't include data about the jetway positions, which is required to create such set.
