My open source project has some daily users, but not thousands. Plenty to attract malicious content, I think a lot of people are sending it to themselves though (like onto a malware analysis VM that is firewalled off and so they look for a public website to do the transfer), but even then the content will be on the site for a few hours. After >10 years of hosting this, someone seems to have fed a page into a virus scanner and now I'm getting blocks left and right with no end in sight. I'd be happy to give every user a unique subdomain instead of short links on the main domain, and then put the root on the PSL, if that's what solves this