There are no accounts. Your private key is the account. As long as you have that, you can always send out notes as your self.

Redundancy, you connect to more than one relay, and broadcast your messages to all of them. If one deletes anything, you have other backups.

Sovereignty, you can host your own private relay, when you post, all your notes are broadcasted to your relays as well, this way, you always have a backup of everything you send out.

Hope this helps. Not really sure if it covers all your concerns.

Paging #asknostr