You are rooted.. just disable Bluetooth completely. No Bluetooth for Android Auto and for everything
.. kmm how to do it in tasker is the real question
I disabled Bluetooth on my 2nd phone (connected to Android Auto, constantly connected, I just leave it in car) and my main phone is connected via Bluetooth (for calling,music,etc).
That's just one solution.
second solution is cloning mac adresses (both phones have same mac). But it doesn't work on all HURs (restrictions).
Sent from my Redmi Note 5 using XDA Labs