Viewfinity S9 - no audio output on USB

[Sbest58]

I cannot change Audio output to USB in settings. I want to route the audio through my MacBook Pro  and into my studio monitors. I have a SSL12 audio interface that is recognised as an audio input and output by the Mac using usb-c cable. I have unplugged the SSL 12 and used the same cable to connect the S9 direct to the Mac. S9 does not recognise the usb connection in the audio output settings and the Mac does not recognise the S9 as an input device. Even trying Bluetooth the S9 only acts as a speaker and does not give any audio output.

[Sbest58]

just went out and bought a usb-c to audio (headphone) adaptor - again no audio output from the S9

[Sbest58]

now tried DP socket - again no audio being output.

So, 3 usb-c sockets, 1 Thunderbolt and one mini DP socket and none of them can output audio. the only way to get any output from the S9 is with bluetooth to AirPods.