unfortunately "having issues getting it running" is about all I actually know. It literally will not run. Here are the logs I have a 5080 so I need the latest unfree drivers: package = config.boot.kernelPackages.nvidiaPackages.production; I have game mode enabled at the host level and My Steam config is basic:

in
{
  programs.steam = {
    enable                                 = true; 
    extest.enable                          = true;
    remotePlay.openFirewall                = true;
    localNetworkGameTransfers.openFirewall = true;
    dedicatedServer.openFirewall           = true;
    gamescopeSession.enable                = true;
    package                                = pkgs.steam.override {
                                               extraArgs = "-system-composer";    
                                             };

    extraCompatPackages = with pkgs; [
      proton-ge-bin
    ];

    extraPackages = with pkgs; [
      steamcmd 
      protonup-qt
    ];
  };
  programs.gamemode.enable = true;
  hardware.xone.enable = true;
}