Please. Captcha by default. Email domain filters. Auto-block federation from servers that don’t respect. By default. Urgent.
And yes, to refute some comments, this publication is being upvoted by bots. A single computer was needed, not “thousands of dollars” spent.
There honestly, are not many tools for even being able to track those down currently.
The only tool really available that can do the job, is writing and running reports directly from the database.