Call it something like greentext or confessions or something. Anyone posting is automatically set to Anonymous with no link whatsoever to the original account for admin or users to track or in the logs/activity pub etc. Like the person will not get replies, notifications on their account for the post, or the ability to reply as Anon. Simply streamline creation of a throw away account using the existing credentials of an existing account for post access and to give automod a chance to act. Maybe bar new accounts or below a certain threshold of engagement.
Yeah, I’m kinda volunteering for the mod part. In truth I think it would take the respective instance admin setting up such a thing specifically. Like create a throwaway or something so that the actual user is not propagated to other admin or the full activity pub feed being transported. The one instance admin would know and have the ability to filter or block, but that information would never escape the one server. As a mod I would be blind to actual potential bad actors and only filter at the liberal community and comments level. So basically a normal community that replaces the OP name with Anon, and never shares the real ID with anyone.