Huge problem with Adobe Connect on an iMac

I'm an online trainer who uses Adobe Connect every week. I have had to give up using Adobe Connect on my iMac because every 5-10 seconds Adobe flashes up the message 'microphone disconnected' followed a few seconds later by 'new microphone found'. It sometimes flashes the same message for the camera as well. I have tried various headsets (wired and wireless) and even the onboard iMac camera and mike. No improvement. Crucially, I do not get this problem when I shift to a 2014 PC running Windows 10. I've used my own professional network. Adobe support Community and everyone is stumped. So, a 'Noble' prize to anyone who can crack it! Some details

iMac (2021 3.8 GHz 8-Core Intel Core i70 running Sonoma 14.0.

I've granted every permission possible to allow Adobe access to mike, camera etc

I am using wired internet access (direct to router). Connection health is fine.

One thing I've noticed in some other platforms (such as Cisco's Webex) is that if my iphone is nearby, the iMac helpfully decides to use the iphone camera (which is usually pointing at my midriff :(. Wonder id just device confusion might be the source of the problem. Thanks for reading this!