And what do you back that up to? Presumably not itself?
I have bought a sub 25watt mini PC and have used something like StartOS to use the FTP over TOR. Plus you could run your own Private Nostr Relay, vaultwarden for password management, and a personal Comms server. You hook it up at a family member's house and put it in a closet with a big sticker that says "Before unplugging talk to nostr:npub1wnlu28xrq9gv77dkevck6ws4euej4v568rlvn66gf2c428tdrptqq3n3wr "
That's worked pretty well so far.
Discussion
That IS the backup. I gave my main PC and web server at my house. All backups are pointed to the mini PC. I have a cal backup on site then the redundant backup off site at a family member's house. (Different state entirely). You could theoretically backup the backup to a cloud service but I don't trust them nor do I want the process to take a day, like you said.