I think functional distros like Guix or Nix are just another thing. Their ability of programming , provisioning and deploying software environments is unparalleled. My personal favorite is Guix since, while having less packages than Nix, it has the most consistent experience: everything is in Scheme from the top to the bottom of the distro. Also it pushes really hard on a sane bootstrapping story while allowing for impurity through channels like nonguix .
The main downside is the lack of tutorials and a documentation that’s very intense, let’s say. typical of GNU projects. I suggest the System Crafters youtube channel which has a lot of nice tutorials
I would say bonfirenetworks.org