Gentoo certainly teaches you a lot, but I would never recommend it to an average user. If you want to get any benefit from use flags for any packages, you will be compiling them from scratch and possibly their dependencies as well. Small packages are pretty fast, sure, but if you try to do something like compile Firefox, you could be waiting all day for that if you don't have a Threadripper or similar.

Practically, unless you run exotic hardware you're unlikely to get any actual tangible benefits from tweaking most use flags on most packages. Which begs the question of why you're using such a low-level distro in the first place...

Idk maybe I just didn't get it, but my month of running Gentoo was mostly just annoying. Again, great learning experience, but didn't make sense to me as a daily driver. It feels like it's for people who want to pore over the detailed patch notes for every package on their system, which is clearly not OP.

NixOS gives me enough control over how individual packages are configured if I really want it, but in a way that stays entirely out of my way until I specifically want to fiddle. I'm not saying NixOS is any better for a new user, but as a pretty experienced one I found it more rewarding once I understood the ecosystem.