nix-configs/modules/desktop/x.nix

{...}: {
  services.xserver = {
    enable = true;

    desktopManager = {
      xterm.enable = false;
    };

    displayManager = {
      gdm.enable = true;
    };

    windowManager.xmonad = {
      enable = true;
    };
  };

  services.displayManager.defaultSession = "none+xmonad";
}