[marcellus23]

If you don't trust the manufacturer, then it doesn't matter whether you turn Face ID off, those sensors are still pointing at your face. Do you physically keep the face ID sensors covered by tape or something? And how do you avoid other people's phones/cameras seeing you?

[warkdarrior]

And if you don't trust the manufacturer, how do you make sure you identified and covered or disabled all of the sensors on the device?

[vel0city]

And you don't trust the manufacturer with a scan of your face, but you put a significant amount of communications and positional data and logins through it.

[catlikesshrimp]

>And how do you avoid other people's phones/cameras seeing you?

You are missing the point.

>those sensors are still pointing at your face

some phones have a popup front camera. The camera is inside the phone. It is obscured and it would be alarming if it pop up on its own accord.