IIRC the software was originally something that Logitech developed but then later open sourced it. In /etc/pulseaudio/default.pa, all you need to do then is adding the following lines according to your own network. Then you can install this on many devices and using the LMS send audio to all those client to be played in sync. sudo apt install pulseaudio-module-zeroconf. It boots quickly and you can shut it down by pulling the plug on the machine without risking file system corruption (everything is in RAM). There is a RPi ready made image called picoreplayer which essentially boots tiny core linux and a squeeze client.

In the case that you want a 'multiple room' solution, or a solution where audio needs to be played both locally and remotely in sync, then you need to have a look at sometihng called Logitech Media Server and squeezeplayer/plug.

There are however some videoplayers that can play the audio track of a file in advance in order to compensate for such latency. There is a latency of about some seconds, so you wouldn't want to watch a film or play a game on it (as the audio would always lag a few seconds compared to the visual content). You can use this as part of another project if you want the Pi to ‘talk’. Using a DW-CT14+ Bluetooth amplifier module and speaker with the Zero W for text to speech synthesis. Then you can send audio from any program from the computer to the RPi (and thus to the amplifier). Connecting a Bluetooth speaker to a Raspberry Pi Zero W running Raspberry Pi OS Lite. This will then add the RPi as an output device in pavucontrol. Then use a script called 'pulseaudio-dlna' on the Debian machine (you have to find the source with google or equivalent). Thread Set proper audio device names on Raspberry pi 4 discusses how to get pulseaudio to display meaningful device descriptions, rather than use the hit-or-miss method I described above. I have then set up DLNA, mainly because so many phones and other devices have DLNA. 1- Yes, I have no doubt that Raspberry Pi with A2DP works fine, if you can’t do that, it is just a matter of software configuration, the main issue is when you try to connect your speaker while the PulseAudio session is taken by other source, or it is shut down after some time. Here is one way that I have done something similar and had it work very well.

Pulseaudio raspberry pi