Directing sound from the iMac out via USB to an Amplifier/DAC/Streamer

Folks, I want to listen to game sound effects and DVD soundtracks through my new HiFi. It is possible to do so via BlueTooth, but there is a significant delay in the sound causing screen and sound to be unsynchronised. It is also possible to use the headphone jack, but the sound quality is low.

I am attempting to send sound from my 2019 iMac running Catalina 10.15.3 out of a USB-C Thunderbolt port to the HDMI input on my Amplifier DAC Streaming device, an NAD M10 with excellent attached HiFi book shelf speakers.

I have tried to use system settings > Sound> Output and the cable/amplifier attached is not registering. Man Cave is the name of the amplifier accessible via Bluetooth, but there's a significant delay between picture and sound.

The Apple support article: Connect to HDMI from your Mac, was attempted with no success, in terms of switching off and on devices.

Contacting Apple Chat Support gave me the following : "... use the cable I have, USB-C to HDMI, then get an HDMI female connection to Male connection cable" which I can't see working.

Has anyone in the Support Community had success using USB-c to HDMI connectivity?

With thanks, Peter