If its possible to create your own instance and federate with any instance of your choice - are there any apps which include the ability to register your own instance with you as the sole user? Maybe I’m misunderstanding the underlying logic

That’s how doubt works.

1. There’s something you know and you experience something which challenges that knowledge.
2. Now you only believe this thing, less sure in your knowledge so you reach out to others who are more knowledgeable on the topic.
3. Post answer your belief has either returned to fact or you’ve learned something new, abandoned a false belief and grown as a person.

Nothing wrong with reaching out.