What does DirecTV have to do with your router?
Ive found QOS to be a POS. It seems to limit everything to some degree and involves overhead.
What you are streaming on the ROKU also depends on where its coming from and the upload speed there.
Before diving into QOS and downloading elsewhere.........Go to Okala (in my speed link) and post your internet speed test. If what you get from the ISP is not sufficient then QOS setting wont amount to a hill of beans.Not talking about advertised speed, this is about actual and with 99% of cable companies actual is a fraction of what you are paying for. If on cable you can QOS your neighbors who all share the bandwidth of that line and all cable companies will throttle you during peak hours and anytime your traffic is what they consider to be excessive. They may say they dont, but they do!! This I know for fact.
“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein