I'm a "full stack" backend dev - I mainly do backend work, but make minor changes to the frontend, like adding a button to a page that already has 3 other buttons.
I've got a couple of friends who didn't want to do even the occasional front end work and moved to devops. They'd rather deal with k8s and monthly on-call rotations than deal with frontend.
I don't know who gave you the impression that all backend devs think of front end as "easy", but it's definitely not the case, at least in my friend group of n=4. We treat frontend as insane arcane magic and we don't want anything to do with frontend because we find literally everything else easier.