What gave USB NICs a bad reputation in the SBC community is that before the RPi4 the USB bus was USB 2.0 (the RPi4 has a USB 3.0 bus) and this meant that the ma

What gave USB NICs a bad reputation in the SBC community is that before the RPi4 the USB bus was USB 2.0 (the RPi4 has a USB 3.0 bus) and this meant that the max speed was 480 MBps if the NIC consumed the entirety of the bus. A USB NIC would never be able to get to 1 Gbps speed no matter what might have been claimed. With the RPi4 you have USB 3.0 on the main USB bus so the max bandwidth there is now 5 Gbps, but the next bottleneck to be faced is the PCIe x1 bus that is used to connect these CM4 modules to the third-party carrier boards. Now you are hitting a 4 Gbps limit.