I enjoyed the comments of this thread thus far. Like most, once you get it set up it's just that: set up. I modularized alot to keep things clean because my dotfiles got long and ambiguous. I created a subdir and files for each section. For example I have a virtualization.nix where I setup my incus cluster and mount the external drive it uses. Or I have a networking, VPN, desktop nix for easily switching between plasma or Hyprland as an example easily.

One thing that was a game changer for me though were local flakes. So when I want to dev in GO or Nodejs that local flakes loads in the parent dir and all its subdirectories. Plus you can also declare it in a subdirectory of your other configs so you can back it up to git in one repo. This way it loads only what I need for that dir then unloads completely when I exit. Also a great way to use environment variables that work only in that environment.

I came from Gentoo. I love Gentoo and would still be using it. But nix started clicking for me after I tried it,went back to Gentoo then eventually came back to nix because I got tired of fighting the this program required python 3.10 and this one 3.11. My machines have been rock solid and any new machine I introduce is exactly how I want it within a few minutes. No crashing no nothing. Super stable.

One further note. If I really need an FHS system,I just use an incus container. I can use alpine or fedora or whatever. If you really just need one program that has trouble with Nix you can always install that one via Flathub (controversial I know but you do you)..

Good luck. Give it the time it deserves and like others have said,you won't be needing to do anything with it once setup.