I've been using a Philips Brilliance 329P1 monitor as one of 2 monitors connected to an M1 Mac Mini for several months, but I hadn't tried to use the monitor's integrated webcam until today. That failed. I'd been connecting the Mini to a Lenovo ThinkVision T32p-20 monitor with a USB C-to-Display Port adapter (Mini USB-C > Apple adapter > DisplayPort cable > Lenovo Display Port). The Philips was connected to the Mini by HDMI. This worked fine for video, but not webcam or microphone.
Reading the minimalist Philips monitor manual, it seemed like I needed a 2nd connection, by USB-C, to make the Philips webcam and USB hub work. But it didn't turn out that way. I only needed to swap the Mini > HDMI cable to the Lenovo, and run a good quality USB-C cable from the Mini USB-C to the Philips USB-C input.
When I tried then to test a Microsoft Teams Classic connection, I now had the Input option (as also in System Settings > Sound > Input) of Input (microphone) via Realtek USB2.0 Audio. I tried the tests in Teams Classic and also later in Zoom and both the microphone and the camera of the Philips webcam worked fine in both apps. I tried to use the New Teams app, but my employer, whose Teams group I'm connecting to, apparently has not enabled use of New Teams.
I'm not sure but I think the USB cable I used for the Philips was included with one of the monitors. It is a red & black braided cable, and on one red connector end it says "RIITOP" and on the other side of the connector is the "10" indicator USB icon.
Hope this helps someone.
PS: I think, from reading the Manual, that the Philips webcam and Hub could be made to work with even a USB-A connection, if you are using HDMI or DisplayPort for video. But I didn’t have a free USB-A port on the Mini so I didn’t try that.