If you downgrade to Android 5.1 you will get exactly the same system as before the update to Android 7. It's important to use restore button method. For Q10 Pro, as here: http://www.futeko.com/newforum/index.php?topic=1392.msg10920#msg10920
Android 7 firmware 2.0.4 requires Netflix version 4. Get it here: https://netflixhelp.s3.amazonaws.com/netflix-4.16-200147-release.apk Earlier firmwares work with most recent version of Netflix from Play Store.
MX Player should work on all firmware versions.