I'm not sure if that spam assault is truly over. Yet there were no new reports or hits on that matter.

I'd congratulate y'all and pat on your virtual backs, but (as a mod) I gotta stay vigilant, and you should do the same for a while.

As for instance admins who might've been affected: take notes and learn how to handle registrations properly so the incident wouldn't happen again. Remember that by federating with the Fediverse you agree to take responsibility for the content that comes from it - whether you like it or not.