Turns out some apps needed adjusting on macOS

With the exception of 1Password, the changes here are for apps not
available on darwin. 1Password was changed around because it must be
installed directly in /Applications to run. I filed this bug report
about the issue: https://github.com/NixOS/nixpkgs/issues/254944

modules/nixos/configuration.nix

@@ -101,13 +101,18 @@ in {
   # List packages installed in system profile. To search, run:
   # $ nix search wget
   environment.systemPackages = with pkgs; [
+    _1password
+    _1password-gui
     dconf2nix
+    firefox
     gnomeExtensions.appindicator
     gnomeExtensions.caffeine
     gnomeExtensions.dash-to-panel
     gnomeExtensions.user-themes
+    libreoffice
     neofetch
     tilix
+    vivaldi
   ];
 
   # Some programs need SUID wrappers, can be configured further or are