Depends on the device. Some allow the bootloader to be unlocked officially. Root is usually needed when you unlock the bootloader unofficially, using some hack.

Also, /e/os supports an official gsi, which can be installed without root.

That said, these phones aren’t suited for people that need absolute security and privacy. They’re more experimental and aimed at enthusiasts of the project who want to support it.

I can see why eos raises some concerns, but i find it to be an interesting alternative with moderate potential. We definitely need more alternatives to standard android.