The way I understand it, the server component is "zero knowledge", meaning you decrypt on clients with your password and the server just serves an encrypted blob. Am I right?
Assuming you're correct, the parent question is still valid. I think you'd at least want to have some redundant backups to protect against loss (not compromise).
Like anything, you just need to backup, I backup from the ui in vaultwarden intermittently onto a USB stick
The apps also work as a backup to some extent (and still let you export even if the server is down)