I have found out why I was not getting the RecyclerView to work. Make sure to add your firebase url in the getInstance parenthesis. Mine was set in Singapore while the getInstance() is defaulted to us-central1. That is why I was not seeing anything:

MainViewModel.kt:

private val firebaseDatabase = FirebaseDatabase.getInstance("[your firebase url]")

Please check logcat located at the bottom-left corner of Android Studio. This was a rookie mistake of mine as I was looking for errors in the build section.