I am having a very strange issue on win 10 LTSC 2019 updated to latest version on my recently assembled desktop. I have an AC wifi usb adapter(Realtek 1200mbps) which has a setting in Device Manager--Advanced titled "QoS". Now if QoS is set to auto or enabled then what happens is that as long as I launch a media player & play any video file, the upload speed drops down to 200-300KB/s from 4-5MB/s & will remain there until media player is closed. Now if I disable QoS then this issue goes away but another one takes its place which is very high latency in local network(even pinging the router gives avg 800-900ms pings) & almost unbrowsable local network speed of 40-50KB/s while trying to access shared folders from another pc in the local network. I have tried all other things like enabling/disabling windows firewall/defender(only using this with no AV), giving preference to IPv4 over IPv6 etc & it all comes down to QoS setting in my usb wifi adapter(my other one does not have this QoS setting). What I am puzzled about is what possible relation can QoS on an usb wifi adapter have with local media playback(I have not enabled media streaming option in win 10). I seed a lot of torrents & really don't want to choose between either watching videos with negligible upload speeds in background or good upload speed with practically no local network connectivity.