Hi awiouy,
thanks a lot. this does help me foreward as it confirms indeed that I would need to create some audio device on libreelec as network sink. This sink I should connect to on docker, and there I can have pulseaudio-dlna connect to it.
After that I can again stream over network, and see (hear) what comes out.
Let's hope the lag will not be too crazy..
thanks again, I now know what I have to do,