Thanks Mario for those clarifications! 🙂
It is true, the BT feature is not really working well on zero and 3. So I gave up on using Kodi (libreelec) as single media source streaming via Bluetooth to my raspi zero to stream it from there to the LMS BT-in. I just could not establish the BT connection between the pis. The 3 discovers the zero but cannot connect. The zero discovers the 3 very rarely and no connection is established.(benchmark: the BT connection is what pcP does very well with those pis)
Maybe a new try with better hw in the future.
For now I’m very happy with my setup and am living with the small things to improve in the future:
1. I need 2 apps, 1 for multiroom music listening (squeezer) and one for TV: yatse.
2. When I switch of my devices I need to click my http command for shutting down max2play before cutting power to spare the SD card.
Just one question again: As soon as I have the BT-in stream working on the LMS, this stream can be played synchronously on all players connected to the LMS (this is what I could not accomplish with pcP, since the stream is only played on the player that is connected to the BT input device (e.g.Raspi with kodi running on libreelec))
Thanks and best,