I've never rooted my phone for LineageOS (and I have installed it on at least a dozen phones now). The only thing you need to do is unlock the bootloader (which you cannot relock, like with Graphene).

>The only thing you need to do is unlock the bootloader (which you cannot relock, like with Graphene).

GrapheneOS not only permits relocking, it prompts the user to do so immediately after installation.

A stock OS never presents root. Finding an exploit or unlocking the bootloader will allow you to install Magisk.

Lineage always presents rooted ADB in the developer options; it is "pre-rooted" for you.