Interesting as I'm having issues with a Philips 346P (Philips Brilliance 346P1CRH).
It was working fine before Big Sur, but after the update it is no longer working.
Sound preferences - Output
Name: PHL 346P1C
Type: DisplayPort
Settings for the selected device: The selected device has no output controls
Output volum: Max (disabled)
Mute: disabled
Show volume in menu bar: true
Tim-H
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