a password vault contains a lot of long-lived secrets protected by a human-provided key, so it's really not something you want out there, even encrypted.
I’m aware that this is security through obscurity. The instance’s accounts use strong passwords and MFA.
Sharing features did you mean organization, bitwarden send ?
I do think that while selfhosting is admirable, in the case of your password vault, it's not. It's one thing where I'd always advice against selfhosting or DIY, because the downside risk is just too big.
The chance of fng up may be tiny, bit if you fck up, it's bad. Potentially bankruptcy or jail bad.