Need help with nix-vscode-extension overlay

nix-vscode-extension: GitHub - nix-community/nix-vscode-extensions: Nix expressions for VSCode and OpenVSX extensions [maintainers: @deemp, @AmeerTaweel]
I have a basic flake like this:

{
  inputs = {
    nixpkgs = {
      url = "github:nixos/nixpkgs/nixpkgs-unstable";
    };
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    nix-vscode-extensions.url = "github:nix-community/nix-vscode-extensions";
    hyprland.url = "github:hyprwm/Hyprland";
  };

  outputs = { nix-vscode-extensions, home-manager, nixpkgs, hyprland, ... }@inputs:
  let
    username = "kahlenden";
    hostname = "Windows11";
    system = "x86_64-linux";
    pkgs = import nixpkgs {
      inherit system;
      overlays = [ inputs.nix-vscode-extensions.overlays.default ];
      config.allowUnfree = true;
    }; 
  in
  {
    nixosConfigurations."${hostname}" = nixpkgs.lib.nixosSystem {
      inherit system;
      specialArgs = { inherit inputs; };
      modules = [ 
        ./configuration.nix
        home-manager.nixosModules.home-manager {
          home-manager.useGlobalPkgs = true;
          home-manager.useUserPackages = true;
          home-manager.users.${username} = {
            imports = [ ./home.nix ];
            home.stateVersion = "24.05";
          };
          home-manager.extraSpecialArgs = {inherit inputs username; };
        }
      ];
    };
  };
}

and even though i have define the overlay overlays = [ inputs.nix-vscode-extensions.overlays.default ];, in my home.nix (home manager as a nixos module), it doesn’t recognize the pkgs.open-vsx;

{pkgs, ...}: {
programs = {
    vscode = {
      enable = true;
      package = pkgs.vscodium;
      extensions = with pkgs.open-vsx; [
        sainnhe.everforest
      ];
    };
  };
}
 error: attribute 'open-vsx' missing

       at /nix/store/7jc0qcwlvlyhlirsl0y40dlilwa89x3g-source/home.nix:58:25:

           57|       package = pkgs.vscodium;
           58|       extensions = with pkgs.open-vsx; [
             |                         ^
           59|         sainnhe.everforest
       Did you mean one of openmsx or openmvs?

what have i done wrong here? Please help me…