Hi @amooW6ojoh,
You could use Bot Detection to enforce a Captcha to prevent malicious registrations from happening.
Secondly, you could enforce a requirement for email verification to login to restrict users from logging in until they have verified their email address. See the Best Practice of Enforcing Email Verification knowledge article.
And if you need to perform some validation checks prior to registration, you must use a Pre-user Registration Trigger instead of a Hook because Hooks are no longer supported.
Thanks,
Rueben