Flake + HM Config: Accessing home-manager "config" outside of the module

Help
1

In my system config flake, I have an overlay for a GTK theme which is just overriding some colors and working so far.

I also set up nix-colors to manage my color palettes. The colors are saved inside config.colorScheme.colors.baseXX.

Now, I would like to pass these colors (i.e. home-manager’s config) somehow to my GTK overlay so I do not have to hardcode them. However, this does not seem possible as my system config looks something like this

...
  sys1 = nixpkgs.lib.nixosSystem {

    ...

    modules = [

      ...

      inputs.home-manager.nixosModules.home-manager
      {
        home-manager = {

          ...
          
          users.${user} = import ./sys1/home.nix;

        };

            # no access to config!
        nixpkgs.overlays = [ 
          self.overlays.default 
        ] ++ (import ../overlays) { inherit pkgs; }; # herein is my GTK overlay which I would like to have access to config

      }

    ];

  };
...

Putting the nixpkgs.overlays into my home.nix causes the gtk theme settings to not find my custom theme package… So is there any other solution to get access to config?

2

My current (ugly) workaround is to import my colorscheme.nix a second time and pass it to the overlay import.

nixpkgs.overlays = [ 
 self.overlays.default 
] ++ (import ../overlays) { inherit pkgs; importColors = import ../xxx/colorscheme.nix; };