Your phone isn't needed except as maybe a Hotspot so the radio head can access the internet if you don't have a whole rv router.
Apps work independently.
It's a complete android system unto itself.
It will even do things offline that your phone will like work with Google maps you have predownloaded.
We have an app, radar now, that usually runs on it.
The 9.0(maybe as low as 8.1 version) and higher Android will do split screen so we can have
Showing at the same time.
We keep waze on an easier to reach device. We like to participate in waze and mark/U mark roadhazards and police and such. It's either on a phone or on a $110 10 inch android tablet.
The head will also do
In the background.
I think post 111 in my signature thread shows a bunch of rv specific apps which we can use on the radio head.
It'll do ANYTHING your phone can but on a 10.1 inch screen.
(I think some of these head units even take a Sim card.)