Browser privacy features actively try prevent what you are trying to do, certainly preventing access to the Mac Id. The closest you can get in Perspective is session.device.identifier, though it isn’t guaranteed to survive deliberate attempts to wipe it. I would expect it to be more reliable in the mobile apps.
If you absolutely have to have this kind of reliable device identity, and you aren’t on mobile, Vision is still the only way to get it. Using techniques like this.