Dune plays fine here, you didnt fully say how you got your player hooked up, try HDMI video direct to tv, and HDMI audio to your AVR, my avr wont pass the video for some reason ( well too old for new HDR ) and i get a red fuzzy screen ,
hmm odd, so what glitches ?? sound or picture
well that doesn't make sense if you remove un needed tracks and it works, is the source file corrupt ??, try ripping the disc again
hmm ok, well for test purpose plug the dune directly into your tv bypassing your AVR and see if you get the problems
what movie are you having problems with ?? whats is the file size and what bitrate is the video ?? also what format ?? mkv avi iso ??
Best is SATA next USB3 next USB2 and last is NAS.Maybe a memory problem with menmory hungry APP's installed?
you say you havent tried a different HDMI cable !!, even Porsche and Ferraris break down, so try a different cable