How can I add a USB Ethernet connection in Linux (Ubuntu and Raspberry Pi OS)?
USB ethernet devices will often just work when you plug them in Ubuntu and Raspberry Pi OS. You typically do not have to do any additional configuration or install drivers.
Please note that the blue USB ports are USB 3.0 and capable of Gigabit speeds, where the black USB ports are USB 2.0 and have a much lower speed (up to 300Mbps, best case, but often lower).
Once the connection appears in Speedify, you can adjust the Connection Settings, such as Priority, to control how Speedify uses the connection.