Scrolled deep to find this correct answer. Idk why people backup vaultwardens database somewhere and often.
I had a crash on the machine where vaultwarden ran. I just did a backup on a connected client "after" the crash. Saved all and rebuild a new vaultwarden, simply import and it runs perfectly without a loss. The server is mostly just a bloated secure syncthing. All data is stored in the apps, too.