Gnu Guix. By default Guix uses only free libre software, but there are ways to install it with a non-free kernal. Systemcrafters has a guide (this is what I used) as well as non-guix (guix repo for non free software).
Woah, definitely need to check this out. I wanted to slap guix system on an old laptop but had issues with proprietary drivers, very curious to see what workarounds people have had luck with.
Otoh I barely touch this computer, and NixOs is running fine on it..