BlueALSA is a Bluetooth audio ALSA backend that allows the use of Bluetooth-connected audio devices without the use of PulseAudio or PipeWire.
This is currently only available in Debian Unstable/Sid. It's expected to land in Debian 12/Bookworm.
Install the bluez-alsa-utils package. This supports the LDAC and SBC codecs. AAC support is not compiled into the official package, because the required library is only available in the non-free repository.
This will also automatically configure a "bluez-alsa" systemd service, and install the proper ALSA configuration files to glue everything together. No further steps should be necessary. If you run into issues after installation though, a reboot might help.
The bluealsa command is your main tool for configuring BlueALSA. It's very thoroughly documented in its manpage. Either run man bluealsa or view it from the Debian web interface: bluealsa
Pairing shouldn't require any special hassle, though incompatibilities aren't impossible. The BlueALSA developers recommend using bluetoothctl to pair, the usage of which is documented on the main BluetoothUser page. BlueDevil is a graphical option that also explicitly supports BlueALSA, for KDE Plasma users.
After the device is paired, it is registered as a virtual PCM device with ALSA, which you can play normally. You can list all devices using the bluealsa-aplay wrapper, and running:
More information can be found on the project's official GitHub page: https://github.com/Arkq/bluez-alsa/blob/master/README.md#configuration--usage
BluetoothUser - Main page for general end-user information regarding Bluetooth in Debian
BluetoothUser/a2dp - Main page for Bluetooth audio on Debian, while using PulseAudio/PipeWire