TP-Link UE300 USB Ethernet Adapter
This USB 3.0 Gigabit Ethernet adapter is plug-and-play compatible with Windows, Mac and Linux. There's no drivers required, or even a reboot - Just plug it in and it works. It's also fully compatible with USB-Dolphin for the GameCube! Here's an Amazon paid affiliate link to the exact one I bought: https://amzn.to/4ndlBo2
Here's that extension cable: https://amzn.to/4sJ61S9
...and here's more info on USB Dolphin: https://retrorgb.com/usb-dolphin-usb-...