Like everyone else said, pixels are the best phones for non stock OS. You can unlock them easy and they are quick to release security updates so the open source security nerds who made graphene OS (the best open source OS) love pixel phones.

The problem with newer Samsung (post 2021 is update) is they don’t allow you to unlock the bootloader (at least for US phones). This pretty much squashes your ability to put a new OS on it.

DivestOS is no longer maintained, RIP. Long live Calyx.