Switch off BT when no CAN traffic?
The current support of Bluetooth in the Arduino framework for the ESP32 does not support pairing PIN code. This leaves a too big security loophole IMHO.
We cannot close this hole, but maybe it is a good plan to check if there is still traffic on the CANbus and if not, shut down the Bluetooth stack.
A method could be to count incoming packets, and check that counter for a change every 5 seconds.