Regarding the GTN, there is a setting in the GTN options for it to output the GTN's flight plan as simulator waypoints, which the G500 then automatically reads.
Regarding airspace, we are only showing airspace where we had an available data set for, not all countries had a proper dataset we could use.
Regarding settings, while this G500 is not 1:1, there are map related settings via the menu button -> map setup page, as well as system settings available under the aux group.