Media audio plays on bluetooth or AAWirless?

Below is my understanding of how AAwireless works-

The Phone will pair to the dongle, after being paired, the dongle will start up the Android Auto system. It then will pair the phone to car’s Bluetooth to handle phone calls and then disconnects Bluetooth from the dongle. Then the phone will connect to the dongle over Wi-Fi, and this will allow the phone to interact with the dongle wirelessly to use Android Auto.

Android Auto sends the music audio over USB. AA Wireless sends the music audio over Wi-fi.

In both cases, phone call audio is sent over Bluetooth.

AAWireless system uses Wi-Fi Direct for music and data. Phone calls are the only thing going over Bluetooth when the system is in use.

The difference between the bluetooth and usb/wifi transfer is made by the audio quality. The music that Android Auto sends to the head unit features a higher quality, typically CD quality, so it will need more bandwidth to work properly. Does this have any impact on the battery for AAWireless?

Questions I have -

I notice Media audio button enabled under car's bluetooth, does this mean that the phone is passing all media (HD) audio to bluetooth rather than AA wireless?

Does audio always automatically connect to car's bluetooth?

What would happen if I turn off media audio in the bluetooth settings in the car's bluetooth name?

Will it not play media audio at all or does it play on Android Auto headset for data handed over wi-fi connection to dongle?

2023 Toyota Sienna | Lumina Audio X | Pixel 6a | Android 13

Thank you for your help!