For anyone wondering the current status of this: Fur Affinity have lost control of their Twitter but have manage to get control of their dns back. They're just doing some tests and getting the site back online. The hacking group NullBulge claim to have found out who did it, but I'm not sure I understand their evidence.
And before anyone asks: Both Mastodon and Bluesky use dns to "verify" people, so they wouldn't necessarily have been safer.
Secure your dns, people!