t's a new feature to notify you that the camera is being used. In this case it's by Face Unlock. It also does it with the microphone. Hence the ability was added in Android 12 One UI 4 to have quick toggles for mic and camera so you can have a kill switch incase you dont want an app using mic or camera.

Note hoewever that the icon appeared on the homescreen.

If you see it while watching YT videos, you can bet your ass, YT is watching you.

In my view you have a couple of options:

1. NEVER use a smartphone with a camera + microphone.
2. ONLY use smartphones with hardware switches. Software switches are crap.
3. A YT frontend, like freetube, does not cut it. It often is unable to load the video due to: geo restriction, login requirements, and other "safety" measures.

And since ANDROID-STOCK is built around Google PAY i.e. harvesting your data, you may want to reconsider the value of each element you are using and if that is worthy of invasion of your privacy, especailly since many .govs are abusing that. This leads to 4. 4. USe only smartphones with an alternative to Android OS