You can just use something like YunoHost, and synchronize weekly encrypted backups via Nextcloud or Syncthing to all of your computers. That way, if your server ends up busted for whatever reason, you can just restore it elsewhere and go back to business
Can you use SyncThing along with Nextcloud? I currently use Nextcloud to store my data, but the one part where it still lags a bit behind is on Android specifically (you need to manually sync certain changes).