I have vaultwarden in docker but I don’t expose my instance externally as you really don’t need to. Put the bitwarden app on your phone sign into the instance and it will work even if your instance is borked. You can’t add items but it works.
My suggestion, run it in docker and just back up the entire docker compose and folder structure as that includes the database as well.
If you want to expose it use nginx proxy manager its dead simple and awesome.