admob-plus in Android Studio: make banner invisible on certain pages

I have successfully got a cordova project running with admob-plus plugin in Android Studio. The banners work perfectly on various pages. Google Play has rejected the app because banners are visible on the embedded YouTube pages. I would like to change this and make them invisible on these pages. My question: How can I make a banner invisible on pages with YouTube videos? The banners appear automatically and are above the iframe. My attempts with additional iFrames and z-index always show the admob banner. Even links to external html pages with YouTube videos always show the banner that is superimposed on top. How can I make the banner invisible directly on the pages?

In the header of the html pages I have linked to cordova.js and admob.js and then added these snippets with the corresponding AdUnitID:

<script type="text/javascript" src="cordova.js"></script>
    <script type="text/javascript" src="plugins/admob-plus-cordova/www/admob.js"></script>
    <script>
        let banner

      document.addEventListener('deviceready', async () => {
        banner = new admob.BannerAd({
          adUnitId: 'ca-app-pub-xxx/yyy',
        })

        banner.on('impression', async (evt) => {
          await banner.hide()
        })

        await banner.show()
      }, false)
    </script>

On the html page with embedded Youtube iframe I used the snippet, which does not hide the banner:

    <script type="text/javascript" src="cordova.js"></script>
    <script type="text/javascript" src="plugins/admob-plus-cordova/www/admob.js"></script>
    <script>
        document.addEventListener('deviceready', async () => {
   // Obtain user consent first

   await admob.hide() // or start loading ads

   // Load ads here
 }, true)

Is it not possible to do this directly on the corresponding html page? Do I have to add the MainActivity.java so that I can hide the banner on the YouTube page? I have been looking for a solution for days and would be very grateful for any help.

MainAcitivity.java

package ...
import ...

public class MainActivity extends CordovaActivity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        // enable Cordova apps to be started in the background
        Bundle extras = getIntent().getExtras();
        if (extras != null && extras.getBoolean("cdvStartInBackground", false)) {
            moveTaskToBack(true);
        }

        // Set by <content src="index.html" /> in config.xml
        loadUrl(launchUrl);
    }
}