If the map can't talk to Tesla it'll use Google maps directly. I usually don't allow connections to Tesla on my rooted Model 3
I've been hacking on my car and creating my own self driving models
Code is at https://github.com/d4l3k/torchdrive
They're also at https://github.com/d4l3k/fn.lc/tree/master/static%2Fdiy-self...
The one feature I miss is that there's no voice commands since that requires Tesla's servers but at the same time I also haven't been bothered enough to plug in a custom backend
So the company that goes "we don't need physical buttons since we have voice commands" also goes "you don't need those in underground parkings"?!