Just made a post about "that" issue with the fediverse right now, while also talking about the Alex Linder issue.

tl;dr: block Pawoo or remove media/avatars from it, and turn off open regs if your community is likely to get tons of users.
https://pleromanonx86.wordpress.com/2023/04/11/the-pawoo-problem-open-registrations-and-one-trick-for-dealing-with-illegal-content-posters/