enable webPreferences { experimentalFeatures:true} not working

[BumpyClock]

I am using backdrop-filter in my app and with regular BrowserWindow I can enable experimental features like this

const win = new BrowserWindow({
    width: 800,
    height: 600,
    webPreferences: {
    //   preload: path.join(__dirname, 'preload.js'),
      experimentalFeatures: true, // Enable experimental features
    },
    // transparent: true,  // Important for transparency
    autohideMenuBar: true, // Optional: if you want to hide the menu
    show: false,          // Optional: if you want to show the window later
    frame: true,       // Optional: if you want a frameless window
    vibrancy: 'ultra-dark', // This can be used to mimic the backdrop effect
  });

Doing the same in MicaBrowserWindow does nothing

 const win = new MicaBrowserWindow({
        backgroundMaterial: true,
        width: 1366,
        height: 912,
        webPreferences: {
            experimentalFeatures: true,
        },
        autoHideMenuBar: true,
        show: false,
        
    });