Bit of an odd question.

In my living room I have a projector and both a sonos 5.1 set up (Beam gen 1, symfonisk bookshelf rears, sub gen 2) AND a Denon AVR 5.1 with five ceiling mounted speakers.

We mainly use the sonos sytem because the ceiling one is really loud in the small children’s bedrooms.
 

My Denon AVR is really old and has only one HDMI input so I have a separate HDMI matrix for all my inputs - apple TV, firestick, XBOX etc.

I send the audio signal to both set ups and to the projector using this:

https://www.amazon.co.uk/gp/product/B0B4PPH211/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I am considering getting a new AVR, a DenonX3300W that has lots of HDMI inputs and still using the above audio extractor for the sonos beam, so I can choose between the two surround sound systems.

But what I can’t work out - the only way to use the Sonos system would be to have the AVR volume turned all the way down, and then turned up on the Sonos Beam. But - as the AVR is responsible for the audio output data being sent to sonos - would it mean no audio signal was received by the Sonos Beam, and so it therefore wouldn’t work? Or would it still receive the audio data , that could then be turned up and down independently?

Thanks,

Tom