Is consent required before setting a MAC address on a NIC? I don’t think it’s the NIC manufacturer’s duty to get consent because others fingerprint devices using the MAC address.
For what it's worth, I have been involved with implementing the GDPR properly in a number of reasonably large companies. Sadly a number of people can say this and a vanishingly small amount of companies actually adhere to it properly, so I'd take it with a grain of salt.