Dude. This is the leakiest possible protocol. By design. Even fiatjaf advises strongly against using it for DMs you don't want exposed, because only one person needs to leak their private key. You can't even delete. You have no control over which server your signed JSON blobs *end up* on. There is no panic button privacy / stalker avoidance mode. No. Nostr is for being heard.
Unless you're hosting a private relay, then your data is only as private as the non-Nostr protections and authentications. Nostr itself does less than nothing for privacy.