By now you’re probably at your wits end trying to figure out why your Samsung device is connecting via Bluetooth but Android Auto fails to display. So I’m just going to get straight to the point.
The problem is with your USB cord. If you’re like me and have the Samsung Galaxy A70 type C connection but the cord that came with the phone is type c on both sides you will need to order another cable. Not one from Best Buy or your local gas station. Those are just charging cables and offer no data communications, or at least not on the right connections for Android Auto.
This cable solved my issue and it should with yours as well. If the link no longer works, do a search:
USB Type C Cable, AUKEY Type-C to USB 3.0 Charging Cable