Paperwm

if you're looking for an original distro, you should try void. it's super lightweight. i used to keep away from gentoo because it was a source only distro, i would otherwise go fulltime on it, but now that it also has binary compatibility you should check that out, too.

as for wm, i love wayfire as a floating wm, and sway as a tiling wm.

I recommend you try Gentoo and DWM. You don't have to use this setup forever, but at least try setting it up. Installing Gentoo, patching DWM and st, etc. is fun and it's an interesting experience. If you want to use Wayland, check out dwl and the foot terminal emulator. Perhaps you're actually gonna like Gentoo and stick with it, I think it's a great distro. They also provide binaries for larger programs, so you don't have to compile stuff like Firefox. But definitely try out custom kernels.

Coreboot. As low level as you probably get. Embedded secure element OS maybe

https://gobolinux.org/

Garuda might be worth a try. I used it for a couple months and really enjoyed it, I only stopped because Nvidia drivers kept breaking.

I'd say try anything (except debian) with hyprland, it's the dream of anyone who wants to customize their desktop experience.

As for non-standard distros, try Alpine, Void or if you have a lot of time, Gentoo.

As for distros I'd actually recommend, try fedora or any of it's spins

Opensuse tumbleweed, kde

Debian + MATE Desktop! Lightweight + fully compatible with games/Steam!!!

LeftWM. I've been using it for about a year now and I have no complaints vIt doesn't hold your hand as much as other WMs, but it is extremely powerful if you're willing to do some manual setup.

Fedora rawhide’s an interesting bleeding edge experience. I’d recommend installing fedora minimal and setting up your system from there. The rpm system’s rather robust when it comes to installing the correct dependencies when done correctly so I personally haven’t had any issues with version conflicts.