What this comes back to is... who cares about any of the crypto bullshit? Having a private key and signing everything with it proves nothing because that private key must have a reputation.
You can verify a domain on Mastodon. You can point a domain to a Mastodon server. You can do that with Pleroma. You can make your own alternative to Mastodon that works exactly like how Bluesky works with domains, but it would take a 4th of the time because ActivityPub is simple to implement!!!!