how and when you know it’s a necessity
I did the math actually. And it seems like mass surveillance will only be justified if homicide rates are higher than 20% ( if 1 out of 5 people die in murder ). And only if surveillance actually stops all the crime ( which it doesn't ) and only if there is nothing less problematic that could be used instead ( which there are plenty techniques, like normal regular investigation, where you ask people around on their own terms ). Basically the math says it isn't justified by an apocalyptic margin.
I bought a phone for something like $20 which is very simple. It has no vibration. It has 65 KB of onboard storage. And it is not a smartphone. I don't even take it with me most of the time, because I know that nobody will call me anyway, so why bother. I use it very rarely. The most usage I have from it is calling, flashlight and maybe as a clock once every so often, since I have many actual clocks.
On the computer I use GNU / Linux. And I have no complaints.
So I don't understand why even bother with a smartphone in the first place?
PS: I would love to try Pinephone or Librem5 though.