I’ve used Vaultwarden for at lesst 7 years, I’m sure for longer but I’m not sure how long.
Never had an issue with Vaultwarden itself. Restored from backups several times for a variety of reasons (migrating host, corrupt hard disk, re-installs) and that always worked first try.
In regards to hardering, the wiki has a good guide: https://github.com/dani-garcia/vaultwarden/wiki/Hardening-Gu....
Pretty similar experience for me, albeit I've only been managing it for about a year.
Restore from backup testing was straightforward. We haven't had any problems w/ the application itself.
I used that that hardening guide for my setup. The one I manage is exposed to the Internet and I'm bringing traffic into it via a reverse proxy.