Gentoo’s Portage and NixOS’ Nix are both interesting takes on package management. Both are powerful and open up a ton of flexbility to the user, but still do a lot of work for you.
Are there any other similarly interesting approaches to the package management problem?
VanillaOS has a very basic core system (currently Debian) and builds a completely vanilla GNOME desktop using Nix, .deb, Flatpak, or AppImage. Various package managers can be used to build an application inside of a container. I haven’t used it yet, but I’m planning to give it a try.
Edit: I wasn’t completely correct. It relies on Flatpak or AppImage for the desktop, but allows you to install packages from Arch and Fedora in containers that get exposed to the host OS. Nix is not yet supported.