That’s only if you use their service. If you self host, they get no data from you. My Bitwarden server doesn’t even have access to the internet.

nutbutter answered most of your questions, but yes the original BitWarden also runs in docker. I run my containers inside a VM that I snapshot weekly and keep several backups, so if anything gets corrupted I just restore a VM snapshot. Has never happened for any of my Linux VMs though, only to PFsense a couple times before I abandoned it.

But as nutbutter also mentioned in his great reply, even if you had no backups the client caches will save you.

Sharing costs a fee with Bitwarden, but I only use it for myself so had no real reason to try Vault Warden. That may help you decide which version to try.

Be aware that while it has an iOS client, iOS is REALLY picky about certs these days. It does not let me use certs signed by my internal OPNsense CA, which is really irritating. That’s Apples fault though.

As someone who self hosts Bitwarden, I’m curious why you are interested in switching.