Ok, lets try to simplify the issue.
VW sat nav doesn't seem to show you having moved? On the map it never moves at all?
Where does it show you located?
That sounds like a GPS receiver issue.
Concentrate on that.
Also, CarPlay when running wirelessly uses your car's GPS receiver, not your phones. If you plug the phone in with a cable instead, does your CarPlay nav application work correctly?
But as I say, I'd focus on the VW system not getting a GPS signal. That's a dealer job, probably faulty aerial or receiver module.