@Tony Test cases done: Desktop computer, wired connection using LAN cable → reached 300+ Mbps, the real speed of my connection plan. Desktop computer, placed it beside the modem, as close as possible...

Archer T2U AC600 (US) Ver3.0 is only reaching 55 Mbps. My internet speed is at 300 Mbps, it reaches that when I connect my PC via LAN cable. What I already tried: install driver version 190116 from...