UnityPlayer as a SubView with Transparent Background?

Hello All,

I am trying to do the following on Android (then possibly on iOS) and any advices will be appreciated:

Overlaying UnityPlayer view on top of Native Android view where only the 3D objects being drawn and no camera background (transparent background)

My current progress:

So far I managed to use my Unity project as library into another Android project and assign UnityPlayer view to a FrameLayout on top of another Android view but the camera background color showing... I tried changing the clear flag option to depth only but it didn't work.

I also managed to use a separate GLSurfaceView which I assigned class extending UnityPlayer and implementing GLSurfaceView.Renderer to as the renderer but I am still getting opaque background.

My code as follows:

 // the class extending the player
 class CustomUnityPlayer extends UnityPlayer implements GLSurfaceView.Renderer {
     public CustomUnityPlayer(ContextWrapper context) {
         super(context);
     }
     public void onDrawFrame(GL10 gl) {
         super.onDrawFrame(gl);
     }
 }
 
 // inside  OnCreate function:
         m_UnityPlayer = new CustomUnityPlayer(this);
         int glesMode = m_UnityPlayer.getSettings().getInt("gles_mode", 1);
         m_UnityPlayer.init(glesMode, false);
         
         mUnityView = new GLSurfaceView(getApplication());
         mUnityView.setEGLContextClientVersion(2);
         mUnityView.setZOrderOnTop(true);
         mUnityView.setZOrderMediaOverlay(true);
         mUnityView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
         mUnityView.setRenderer(m_UnityPlayer);
         mUnityView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
                 
         setContentView(R.layout.activity_fullscreen);
 
         FrameLayout layout = (FrameLayout) findViewById(R.id.UnityView);
         LayoutParams lp = new LayoutParams(LayoutParams.FILL_PARENT,
                 LayoutParams.FILL_PARENT);
         layout.addView(mUnityView, 0, lp);

Am I missing something and is it even possible? Any help will be much appreciated.

Thanks alot