I am having trouble imagining the failure mode you are trying to avoid.

It sounds like threads implementation of federation is broken. What effects does toggling that federation setting on or off do?

Like if someone is following “duplicate” accounts of yours and therefore would see double posts, that person can unfollow one. Still double work for you that kind of sucks.

Scuttlebutt had some work done on publicly declaring two identities as the same, I wonder what that would look like for posts. Like a post-id or simple equality comparison or hash could work server side or client side.