I'm sorry, but that's just impossible here. I'm sorry to tell you, but it is.
ActivityPub is a protocol which takes your content and blasts it out to anyone who listens. That's the design of it, that we all listen on our own servers and we can then treat our servers as we want. There is no profit motive on our servers because anyone could just jump to a new server.
However, this means there is literally no opt out protocol. Anyone can start a server, which means anyone can start a server. Governments, corporations, the jerk down the street, anyone. The only way to turn that off is by saying "Defederate from this server", but of course the anonymous nature.. we don't have to know who they are.
Of course we can defederate from other servers but since anyone can spin up a server on any domain, how do you know that Meta doesn't have a server right now at some weird domain? OpenAI could be listening right now and training. In fact I'd be surprised if the site formerly known as Twitter didn't have a mastodon server up so they could keep tabs on it
Even deleting a message is another blast out to all other servers. "Hey, this user requests you delete this message". So what happens if someone modifies their code to just ignore that?
I guess what I'm trying to say is that the fediverse is open and free - and the downside of being open and free is that it's open and free - to everyone. There is no permenent delete. There is no way to way to license it because by clicking post you are saying "Blast this out to everyone who is listening", once it's on their server it's their data. You gave it to them. There is no way to protect data because the protocol quite literally does the opposite.