The Guix package manager is a higly reproducable and stable package manager based on the Nix package manager. It wan made by the FSF, meaning that it allows ou to install a variety of 100% free software. The reproducability and saftey that comes with the Gnu Guix package manager is unrivaled. You may be tempted to install the “Gnu Guix System”, however you can instal the Gnu Guix package manager on any existing Gnu/Linux system. I am going to show you how you can install and use the Guix package manager.
Iirc, Adwaita is the default theme for Gnome and thus most GTK apps. That’s why a lot of packages pull it in as a dependency.