Why I cannot use the USB LAN

Hello Lucario-Lexington,

Thank you for reaching out to Apple Support Communities.

These steps should be able to help:

"If a USB device doesn’t work with Mac

If a USB device isn’t working properly, make sure it’s connected to your computer correctly, is plugged into a power outlet if it has a power cord, and has any necessary software installed.

• Check the power, port, and cable connections: Make sure the USB device is turned on and its cables are properly connected. If your computer has more than one USB port , switch the device’s cable to another port. If you still can’t use the device, contact the manufacturer for more information.
• If you can use the device after switching ports, connect another device to the first port. If you can’t use this device, shut down the computer and unplug it from the power outlet. Wait about a minute, then plug it back into the power outlet and start up your computer.
• If you still can’t use a device with the port, your computer may need to be serviced. See Find out how to service or repair your Mac.
• Check for missing software: Make sure you installed the latest software for your device. Visit the manufacturer’s website for any updates.
• Check the USB hub: If the device is connected to a USB hub, make sure the device and the hub are the same speed. Connect USB 3.0 SuperSpeed devices to a USB 3.0 SuperSpeed HUB, USB 2.0 Hi-Speed devices to a USB 2.0 Hi-Speed hub, and so on.
• If the device doesn’t have a power cord and is plugged into another USB device that doesn’t have a power cord: Try plugging the device directly into your computer’s USB port  or into a USB device that does have a power cord. You might need to disconnect and reconnect the other device as well, if it has stopped responding.
• If you have many devices connected to your Mac: Disconnect all USB devices except the device you’re testing, an Apple keyboard, and an Apple mouse. Make sure that the device is connected directly to the computer, and that any hubs or extension cables are disconnected. If you can use the device now, the problem may be with one of the other USB devices or hubs you had connected to your computer. Try reconnecting them, one by one, to your computer. When you find the device causing the problem, review its documentation for further troubleshooting steps.
• Verify that the device appears in System Information: On your Mac, press and hold the Option key, then choose Apple menu  > System Information.
• In the window that appears, see if the USB device is listed below Hardware in the list on the left. If the device appears but does not work, review the device’s documentation for further troubleshooting steps.
• Reopen apps: Quit and reopen any apps that use the device.
• Restart your Mac: Choose Apple menu  > Restart."

More details can be found here: If a USB device doesn’t work with Mac

If the issue persists, can you provide a few more details? Does this work with any other devices? Has this USB LAN worked previously? Also, which exact macOS version do you currently have?

Cheers!

Apple seems to have been disallowing some older Internet interfaces that have no restrictions on their ability to dump random 'stuff' into memory at high speed. Certain 10G Ethernet adapters are no longer supported in Monterey and beyond. It also appears from your posting that whatever-brand-that-is USB-C to Gigabit Ethernet adapters are not supported.

I can tell you with confidence that this one, available at the Apple Online Store, IS supported:

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