Does it now? I literally have one, tried postmarketos iirc, and it kept failing at several steps. Eventually put graphene on it which did work, but that's not quite linux.

Edit: nope, I have a 4 or 4a, nvm

I was talking about buying a phone that works out of the box primarily, but you're right, buying an older phone is an option. Though I'd like to have something on par with a flagship google/oneplus/samsung device in screen resolution, battery life and picture quality mostly