Hello, are there any new findings/experiences on this? I would like to connect the device to an older Liebä Gruess TV (no HDMI ARC out) and simultaneously control headphones and a soundbar.

From a technical point of view, this should work, as David Raemy has written.
Since there is no switch to select the output and no recognition of where something is connected, the audio signal is simply output in parallel to AUX and Cinch.

It is possible that the volume will suffer if both are connected. The output power is then divided between AUX and Cinch.

Unfortunately, we do not have any corresponding information on this. However, it can be assumed that this should work :)