On devices Android 9+, the Bluetooth discovery doesn’t display any headset.
It’s necessary to activate the Location service for BT Pairing.
To enable the Location service:
Android 9
$ adb shell settings put secure location_providers_allowed +gps
Android 10+
$ adb shell settings put secure location_mode 3
To disable the Location service:
Android 9
$ adb shell settings put secure location_providers_allowed -gps
Android 10+
$ adb shell settings put secure location_mode 0
NOTE:
This process is performed automatically if BT Pairing is installed using the installation bat files of products such as TellNext.