Are you sure? I just bought the Ugreen 2.5Gbps yesterday for this, and it uses a Realtek RTL8156BG chip. That’s the one I used to get way above 2Gbps straight to the UDR.
I have a few cheap Realtek 2.5Gbps dongles spread around my house and get 2.3 Gbps TX and 1.9 Gbps RX (running iperf3 --bidir to a LAN machine with 10 Gbps).
Still beats Wi-Fi by a mile so I'm not complaining.
https://forums.macrumors.com/threads/anyone-seeing-speed-dro...