FWIW, I have no trouble playing any of my alternatively sourced media, 4K Dolby Vision included, using an app called Infuse. Pass-through audio may indeed be an issue for some lossless surround formats, or at least that's what it sounded like the last I looked into it some years ago. I don't have the right room to set up surrounds so it's stereo only over here anyway. But that said I love the app, lovely interface, etc.