I use Iriun Webcam to use my (leftover) Android phone as a webcam into my MacBook Air and iMac, with Zoom, OBS and Quicktime. It works pretty decently, the only gripe is that I can't control exposure from the phone camera so it needs the right lighting to look nice.
There are also other apps out there, besides DroidCam and Iriun, that support different phone-computer connections.
There are also other apps out there, besides DroidCam and Iriun, that support different phone-computer connections.