Yeah so what ppl often do is set up their own private relay. Most node software now offer this.

All you do is rebroadcast your notes and they'll get saved to that relay. If the notes ever get taken down from a particular relay, you can go back to the note (since it's on your personal relay) and rebroadcast it. That'll send it back to all the relays you're on, and now ppl can see ur note again. Basically undelete.