• Sure, I should have gone further.

      Systemd/GNU libc/GNU Coreutils/GNU BASH/Linux/X11//GTK/GNOME
      Systemd/GNU libc/GNU Coreutils/GNU BASH/Linux/X11/GTK/LXDE
      Systemd/GNU libc/GNU Coreutils/Zsh/Linux/X11/GTK/GNOME
      Systemd/GNU libc/GNU Coreutils/Zsh/Linux/X11/GTK/LXDE
      SysVInit/musl/Busybox/tcsh/Linux/csh
      Systemd/GNU libc/GNU Coreutils/Zsh/Linux/Wayland/QT/KDE Plasma
      Systemd/GNU libc/GNU Coreutils/Zsh/Linux/Wayland/QT/LXQT

      etc, etc.

      There are thousands of combinations of the possible layers needed to make an OS.

      • the thing is that not all of them use systemd or bash or zsh or even X11 (servers don’t usually have X11 installed)

        All of them use a Linux kernel and many components that were originally developed for GNU, especially the C library.

        • Except Alpine & those based on it, which uses Linux but not GNU libc or GNU coreutils or GNU BASH… Just musl libc & Busybox. I.e. the entire subject of this thread is one of the non-GNU Linuxes.