The driver does not support the “EU”-class devices (not sure what the differences are) unfortunately.
This is a Ralink device, those need a different driver. It’s on my TODO list to look into.
rtl81xx is a Realtek PCI ethernet device, not a WiFi device.
That driver is old. The mainline one in FreeBSD supports 8812AU/8821AU already. I tested with an 8812AU, works fine.