I'd like to suggest an enhancement to make Bluetooth more user friendly.
On the Radar screen, add another tick box marked BT or Bluetooth.
When this box is ticked, a number of things appear bottom right of the same screen.
There's a small status indicator to say if BT is connected.
There are buttons for up, down and mute for BT volume.
If space was a problem, the you'd stick with status and mute.
I realise that the necessary under the hood may not exist for these controls yet, but it can be controlled on the Pi, from my research.
This would get around the fact that the 3.5mm jack out of the Pi is often "dirty", and has low level interference on it in some installations.
Using a ground isolator results in a signal level drop that makes the audio too low level to be used... so it has to be boosted. That requires an active component.
Using BT gets around any earthing or interference pick up problems. It also makes for easy connection to any intercom with Bluetooth without getting into connector, balanced/unbalanced and level rabbit holes...