A lot of emacs customisation ought to be unnecessary. And I think the yak shaving on one’s config isn’t really a great use of time (if you want it as a hobby then I guess that’s fine).
Some examples of unnecessary customisation is the fact that the defaults of emacs so often ought to be changed. E.g. why does M-SPC do just-one-space instead of the strictly more powerful cycle-spacing (answer: probably a combination of history, neglect, and a fear of breaking existing saved keyboard macros), why use upcase-word instead of upcase-dwim? Why does autocomplete require so much customisation?
If emacs had better defaults there would be much less reason for spacemacs or doom to exist.
One person I work with will (drastically) customise the key bindings for each new mode before using it, making it hard to use new modes. Another gave up on customising emacs and switched to spacemacs to no longer have to think about customisation.