The widely held consensus seems to be that phone hardware has significantly better cameras than even fairly expensive standalone web cams. For both Android and iPhones, there are numerous (semi)commercial software solutions that turn your phone into a camera+microphone.
Does someone feel like creating one for SFOS?
Maybe some helpful info on the old forum: https://together.jolla.com/question/95237/using-camera-as-webcam-for-pc/
Maybe something based on QmlVLC?
But I’m not a developper.
libvlc wrapper for Qt Quick 2/Qml.
Requires Qt 5.x.
Platform independent, and should work on any platform supported by Qt and Vlc ( but was tested only on Windows/Ubuntu Linux/Mac OS X ).
Simple usage demo is available: QmlVlcDemo
Not sure if related but I’ve thought about using my phone as a ‘mirror’ for when I’m on my bike. So a wired webcam device on the back, phone in holder on front, video horizontally flipped.
Never tried it, but maybe juppi ‘Screen casting (beta feature)’ … just an idea…
https://openrepos.net/content/mkiol/jupii
Send screen to projector points to @coderus screencast maintained, I believe by @nephros
I guess essentially you are looking for takimata / harbour-sailstream · GitLab , which I started developing when the pandemic began 
Use case was using the phone’s cam+mic in various online meeting tools.
Unfortunately it doesn’t really work well with the newer Sailfish releases, and setting up SSH port forwarding first isn’t that user friendly either…
I’m currently working on a rewrite for the backend (both sender and receiver) which aims to resolve these issues and should be easier to maintain, too. The individual components are coming together nicely, but I don’t see a release date yet. As always, it’s ready when it’s ready 