Confusion on setting up both Builtin and BT GPS

[Torx]

alright now that we have the builtin gps enabled im completely getting frustrated on setting up both builtin and my BT gps unit.
If im ever in a situation where i need to know my location and my BT gps isnt around then i wanna be able to use the builtin.

But if im on a roadtrip and i want pinpoint accuracy then i wanna be able to use my BT gps.
Now.. between the bluetooth settings, the external gps settings, and my preferred gps apps settings.. com ports, etc.. im confusing myself quite easily.
Does anyone have a solution for me??

EDIT: at the same time i dont want both being on at the same time if im using my BT gps..