I think the only way to avoid surveillance is to not use their system that enables that.

No baseband modem, no arbitrary blobs, no OS that sends data. And should be obvious: no messenger apps that can't be verified.

The problem though is not your phone if you set it up right: it's your contacts. Your opsec is worth a shit if any (and I mean _any_) of your friends uses iOS or not Graphene or LineageOS. And this _any_ also means _any_ security bug that is unfixed which alone by itself is not guaranteeable.

Humans are bad at time awareness, and that's the strength of surveillance systems.

I'm currently working on porting Mobian (or Nix, haven't decided yet) with Plasma to the Hackberry Pi device. In my opinion that's the first untrackable device due to it relying solely on Wi-Fi. Combined with an Atheros Wi-Fi USB stick this has the potential to avoid surveillance altogether, well, given the right tools for enforced randomization, tunneling, scattering etc.

[1] (not ready yet) https://github.com/rogueberry

[2] (there's more alternative versions) https://github.com/ZitaoTech/HackberryPiCM5