Do you think a hardware cutoff switch for the camera, like the Librem 5 and PinePhone, is enough to ensure privacy, or would you really want an actual built-in camera cover like is on some laptops (that presumably also kills the power since the system knows whether the camera is covered). The caveat for only having a switch being that you can’t very easily audit the circuitry to check if it’s actually turning off the camera, but the benefit being that it’s easier to implement, has fewer points of failure, and will leave more room for a bigger camera.
Also, would you want separate switches for front and rear facing cameras or are you okay with turning both of them on and off with one switch?
Okay so, this is complicated.
Kill switches first.
There is really no way to verify that the kill switches are working other than the OS telling you so, unless you are experienced enough to verify yourself.
Even if you verify that they are properly wired, there’s nothing to say that they don’t stop working at some point.
Now, the phones.
There are no Android phones with kill switches that I’m aware of as of this time. Linux phones are egregiously insecure and should be avoided at all costs. They lack protections for almost any attacks made in the last decade, they lack consistent software updates, any coherent security model, and more. GrapheneOS and iOS are the only two secure mobile OSes, everything else is lackluster. If Graphene is a ten and iOS is a nine, mobile Linux operating systems are well into the negatives.