Hi again @hng. Here’s the detail provided by my colleague:
Location: London.
Connectivity: Via Windscribe VPN with UK endpoint. Min 34 Mbps Plusnet broadband.
Latest Mac OS on a Macbook.
Latest Firefox, but also tried the latest Safari with no improvement in audio.
The mic is integral to the Logitech Brio webcam.
Consistent audio problems with meet.coop. Three out of three times now. Nothing vaguely similar with Zoom, Teams, Facetime, or Skype