electron-builder custom install path

I have the below build script:

"build": {
    "appId": "com.yourcompany.gamelauncher",
    "productName": "My Game",
    "directories": {
      "output": "release",
      "buildResources": "app-resource"
    },
    "files": [
      "dist/**/*",
      {
        "from": "assets",
        "to": "assets"
      },
      {
        "from": "../dist/app",
        "to": "app"
      },
      {
        "from": "./build",
        "to": "build"
      },
      "./package.json",
      "./.env"
    ],
    "win": {
      "icon": "icon.ico",
      "target": [
        "nsis"
      ],
      "signAndEditExecutable": true,
      "requestedExecutionLevel": "requireAdministrator"
    },
    "nsis": {
      "oneClick": false,
      "allowToChangeInstallationDirectory": true,
      "deleteAppDataOnUninstall": false,
      "include": "build/installer.nsh"
    }
  },

When the user selects the installation path, I want to create a root folder that contains two subfolders:

Launcher → contains all the binary files and will be updated later by electron-updater.

Game → contains the game files, which should remain unaffected when the Launcher is updated.

How can I configure this setup so that updates with electron-updater only affect the Launcher folder and do not overwrite or remove the Game folder?

Also, if I separate the installation this way, will it have any impact on how registry entries are created (for example, app uninstall path, version info, etc.)?

I have the custom install file as the below but it doesn't work:

!macro preInit
  StrCpy $INSTDIR "$INSTDIR\Launcher"
!macroend

!macro customInstall
  CreateDirectory "$INSTDIR\Launcher"
  CreateDirectory "$INSTDIR\Game"
!macroend