So far pretty content with version Volumiobuster-3.061 on the rPI-4-8GB.
The pro-ject pre box S2 digital is working and sounds perfect.
There is a big improvement on the stability of the Tidal and Qobuz integration.
With version2 it lagged, crashed and had a mind of it’s own. The only way to mess them up in V3 is rapidly skipping back or forward. Then it looses count and Volumio does whatever it desires. 
Not sure what the loopback thingy is doing in the left menu?
Some suggestions:
- Make timezone and localization setting part of the setup.
- During the library scan (50000 tracks), the spinning wheel is not persistence. So it seems done, but then only 10% has been scanned, while it is still scanning.
Found one issue with Qobuz on the iPhone, when using airplay to volumio, volumio drops the connection. After turning shairport off/on in volumio i can reconnect. But nothing is being played.
http://logs.volumio.org/volumiobuster/9Yucnf6.html
Now the being pigheaded part (No need to offer solutions as it is not part of Beta testing):
- Spotify plugin (Team volumio) installed, showing track info, but no audio yet.
- MPD Oled plugin is working, including CAVA for Tidal, Qobuz and Music library.
- GPIO plugins complains on kew. So did the Spotify plugin. But that solution didn’t work for GPIO
Conclusion, I’ll stick with V3 as the beta seems more promising/stable than V2, which caused me almost to move back to JRiver.