Here's a resolution I found. Set your vehicle system back to the defaults. That should resolve your issue. It seems the USB port in the Bluetooth connection we're having a conflict. Once you reset to the default and plug your USB connection you should not have this issue because you did not connect to Bluetooth.
I hope this helps...
I had the same problem after upgrading from the S9 to the S20 + 5G Verizon. I believe the problem is from transferring data from the old device. I factory reset my S20 and Android Auto worked on the first try. Interestingly enough the S20 came with Android Auto already installed. You will need to install the Android Auto for Phone Screens app only if plan to use it without your infotainment system.
Resetting the phone was a pain but I'm glad I did it. The phone seems to work better all around.
Hope this helps.