Unable to build Google VR app for Android

I am trying to build an Android VR app/game. I use Unity 2019.3.4f1.

The new Google Cardboard XR plugin does not seem to work. I am not even able to run the 'HelloCardboard' scene from the Samples package in the editor. This is the error that I keep getting when I try:

DllNotFoundException: cardboard_api Google.XR.Cardboard.Api.HasDeviceParams () (at Library/PackageCache/com.google.xr.cardboard@8979e065b7/Runtime/Api.cs:101)

The generated APK too doesn't work on Mobile Device. The app starts and displays a black screen and nothing else.

Also, when I try to use the deprecated GVR SDK (Google VR SDK for Unity), I get another error message while building APK:

More than one file was found with OS independent path 'lib/armeabi-v7a/libgvr_audio.so

The app/game runs fine in the Unity Editor with the GVR SDK even though it is deprecated. But I am unable to build the APK file.

I don't know what is supposed to be done to resolve these errors. Is this a fault with the SDKs or is there something else that I should have done in order to make this work? Please help.