The code mentioned in https://docs.arduino.cc/tutorials/opta/mac-address/ can return an incorrect ethernet address from:

...and returns an incorrect WiFi mac address for:

I modified the code under https://forum.arduino.cc/t/invalid-mac-address-for-opta-wifi-device/1396321/2 to return the correct ethernet mac address but I don't know what to do about the wifi mac address.