the great update

system/vnc/default.nix

@@ -0,0 +1,11 @@
+{ pkgs, lib, ... }:
+let
+  use-vnc = pkgs.callPackage ./use-vnc-script.nix { };
+in
+{
+  environment.systemPackages = with pkgs; [
+    x11vnc
+    wayvnc
+    use-vnc
+  ];
+}

system/vnc/use-vnc-script.nix

@@ -0,0 +1,10 @@
+{ pkgs, lib, ... }:
+pkgs.writeShellScriptBin "use-vnc" ''
+  if [[ $XDG_SESSION_TYPE == "x11" ]]; then
+      x11vnc -display :0 &
+  else
+      wayvnc 0.0.0.0 &
+  fi
+
+  sudo echo $! > /var/run/use-vnc.pid
+  ''