Reconnect headsets automatically
Your device can connect to the headset or speaker you used last when Bluetooth comes on. Not every device has this option yet.
Open Bluetooth > turn Reconnect headsets automatically on or off.
A device you disconnect in the Bluetooth app is not connected again until you connect it yourself.
Checked against the LuneOS code and installed apps. Nobody has tried these steps by hand yet, so tell us if something differs.