Change mac id of usb-c to lan adapter
macOS has always been &quot;iffy&quot; when it came to spoofing MAC addresses unlike other OSes so it's not a (faulty) hardware issue.  It's more of a &quot;how Apple likes to do things&quot; issue.
My advice is the following (in order):

Get that MAC address registered with the university.
Use SpoofMAC to, well, spoof your MAC address.

Yes, I think you should just bite the bullet and register your MAC with the university.  Yes, it's a PITA, but the downside is simply too costly for the time you're attempting to save.  If they happen to catch you (and they can), you're going to face disciplinary action because in the end, you agreed to their terms of service whether you remember agreeing to them or not.
That said, there are genuine uses for spoofing your MAC address and to do so on a Mac, you can use SpoofMAC.  It's available via GitHub (see link above) or via Homebrew.
Once you have it installed, you simiply execute the following command with the actual MAC address and your network device as needed:
% spoof-mac.py set 00:00:00:00:00:00 en0

They also conveniently provide instructions for launching this at startup.