How can I set a bluetooth default controller
Solution 1:
using list command in bluetoothctl prompt will give you the list of controllers with their mac id, also showing which one is the default
[bluetooth]# list
Controller 14:16:91:15:F6:A0 david-acer #2 [default]
Controller 14:D3:A7:56:F4:D0 david-acer #1
type select command with the mac id of the desired controller to use this controller as the default
[bluetooth]# select 14:D3:A7:56:F4:D0
Controller 14:D3:A7:56:F4:D0 david-acer #1 [default]