@Jens,
did your B&O dealer never tell you about integrating or connecting the Core with the BV Avant?
That is what is called NetworkLink.
If you do that, you will have new sources in the source list of the tv - the socalled linked sources.
You can start these from there and the volume is controlled via the Avant/the BROne.
You can read about this in the User Guide of the Avant.
Note: there are some further steps to make for the Core using the Bang & Olufsen app.
MM
Location: Flensborg————Danmark