Its like a 5 hour job to get something that technically works and then a 10,000 hour job to get something that works flawlessly. The Apple integration with the iphone and macbook is the most seamless setup I've seen so far but I've still gone back to just using the built in webcam because its too fiddly to put my phone up on the screen and occasionally have issues where it won't connect.

Phone as webcam just doesn't seem like a long term solution, eventually built in webcams will be cheap and good enough. And tbh I find the built in one on the macbook to be bordering on good enough once you consider how compressed and tiny the output will be on the other persons screen.