You asked me to help you find the examples and I said no and suggested a technique that might work. It’s an answer, it’s just one you didn’t like. When you told me that you weren’t able to apply the technique successfully, I said
Oh well. It sounds like you’ve got some work to do. The revised version of the article has some antiracism resources, so stay tuned.
There’s a bit more on Mastodon then Lemmy - https://docs.joinmastodon.org/user/moving/#migration has the details. But not being able to move posts is a big limitation. And even the functionality that’s implemented has some unpleasant surprises – see https://erinkissane.com/notes-from-a-mastodon-migration