>Ssl certificates have been facing this problem for years.

That's an entirely different, and much easier problem. In the case of SSL you are not worried about an attacker obtaining a certificate for any host, just the ones you care about. E.g. an attacker getting a certificate for facebook.com would be catastrophic, but an attacker getting a certificate for a website that no one uses would be a non-issue.

For the case of avoiding deepfakes, you need to avoid the attacker extracting a key from any of the millions of cameras that are sold every year.