Hello
Thank you for your question and reaching out. I can understand you are having query\issues related to mute the audio.
Regrettably, Group Policy cannot dictate choices or actions on a specific device. You can disable the volume icon in the Control Panel as a workaround. After that, turn off Control Panel using Group Policy. Nevertheless, all of the control panels will be lost for your users.
Additionally, you might just turn off the sound service for your consumers.
Reference :
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