NixOS consist of a bunch of options that you define using the nix programming language. Since it's a programming language, everything is well defined and organised into single place.
Technically, someone could build a GUI configuration editor with sane defaults and clearly organised pages of settings, which generates a configuration for you. This could immediately change NixOS from the most tedious to a relatively easy to use distro.
Do you know if any tachi forks have bulk migration? I'm on aniyomi and it only support migrating individual titles. Given entire manga sites can collapse overnight, bulk migration is becoming an important feature.