Help w/ QNAP, routers, and Media (Plex, Kodi, QMedia...)

I posted some of my struggles in another subreddit, but basically, I keep running into issues with videos locking up and buffering. My setup for a few years has been a QNAP TS-451+ and an Xbox One, both networked into a Nighthawk AC1750 router.

So I don't know if it's recent updates to Xbox or QNAP or what, but this problem just started a couple weeks ago. I've tried turning off Direct Play/Direct Stream in Plex, that only worked for some videos. I'm mainly watching 720p and 1080p MKV files.

So here are my questions: Would it be better to connect my QNAP to the router as a NAS via the USB SS port (3.0, I think?) Would changing to CAT 6 cable change anything? Do I need to take some sort of nuclear option, like a server with a faster processor?

I'm sort of stuck; I've tried a variety of media apps and tweaks to the QNAP, but I'm not getting anywhere. Any advice is appreciated.

Submitted by bourj | #Specialdealer Special Offer Online Shopping Store 2016