The Vero 4K+ has 4K HDR in beta right now. I don't think the Roku devices can do bitstream audio passthrough but am not really sure here. There's a also a client question / preference. It's basically either a Mezzmo client app (i.e. Roku, Android etc..) or Kodi with the Mezzmo addon (i.e. Windows, LibreElec, OSMC / Vero 4k, OpenElec etc...).