I agree that it would be awesome to use an iPhone in this context. But given the problems my friend has, and given the problems in general with mac wifi and latency, any use as a webcam would be far better if it were wired. Hopefully that will leave a niche for this company. That, and using Android phones, and hooking any phone to a Windows box.
Maybe try Googling again?
https://www.theverge.com/2022/6/6/23156834/apple-iphone-webc...
As for the issue with wifi, that's a legitimate shame for your friend, but isn't a reason for the feature not to exist for anyone.