If you are an advanced linux user then I would suggest giving a try to the following distros: arch, void, gentoo and (like you said in the post) nixOS.
The reason behind is that this distros are focused on the tinkering aspect of linux, the experience of setting up everything the way you want.
If you want to give a shot to WMs I would suggest i3, sway, dwm, dwl, river, bspwm, Qtile and hyperland (maybe focus more on the Wayland ones if you want to try the latest software).