Add UI elements to ARCore SceneViewer (3D model viewer)

Question

I launched a Scene Viewer (3D model viewer) using ARCore in my Android app, and I would like to add custom UI elements like buttons or textual elements to the SceneViewer. Is this possible?

This is how I launched the 3d object in ARCore SceneViewer, as per the documentation (https://developers.google.com/ar/develop/scene-viewer)

How can I add UI elements (buttons, text, etc) to this 3d object view? If someone could point me to documentation, that would be great.

val sceneViewerIntent = Intent(Intent.ACTION_VIEW)
val intentUri: Uri = Uri.parse("https://arvr.google.com/scene-viewer/1.0")
    .buildUpon().appendQueryParameter("file", "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0/Avocado/glTF/Avocado.gltf")
    .appendQueryParameter("mode", "3d_only")
    .appendQueryParameter("browser_fallback_url", "www.ebay.com")
    .build()
sceneViewerIntent.data = intentUri
sceneViewerIntent.setPackage("com.google.ar.core")
startActivity(sceneViewerIntent)