hi sorry to bump this,
im having the exact same issue as OP, my samsung TV wont load anything on third party twitch app or TV Plus app, i originally thought the apps were just buggy or broken, but used 4g hotspot and everything works fine. i tested back on Ethernet with no luck, but as soon as i turn off qos everything works, ive tried all the things suggested in this thread, i have a XR500 on V2.3.2.130. is there any update from devs or anyone else who was experiencing this issue? i dont really want to have to disable qos everytime i want to watch something on my tv.