Since the vault is end-to-end encrypted, it shouldn’t matter where it is hosted, even if it is in the cloud. Here is what a security researcher and a password cracker Jeremy M. Gosney has said about this after the LastPass incident.

”Is the cloud the problem? No. The vast majority of issues LastPass has had have nothing to do with the fact that it is a cloud-based solution. Further, consider the fact that the threat model for a cloud-based password management solution should *start* with the vault being compromised. In fact, if password management is done correctly, I should be able to host my vault anywhere, even openly downloadable (open S3 bucket, unauthenticated HTTPS, etc.) without concern. I wouldn't do that, of course, but the point is the vault should be just that -- a vault, not a lockbox.”

What is your threatmodel here?

The problem for me with completely self hosting it is that it'll be relatively hard to get my backup, availability and sync requirements satisfied without a lot of effort.

Whereas I trust encryption in theory enough to hand my encrypted data to anyone. If the implementation is properly audited then I also trust that.

Most of my passwords are for accounts with 2fa anyway so even if both the storage leak and the encryption turn out to be subpar my threatmodel is still not violated.

If self-hosting makes you feel better about it, Vaultwarden exists for the Bitwarden client.

I'm using both. Mainly I use KeepassXC for most stuff (including my Proton account) because aside from the other security things it offers (like encrypting the database with a keyfile and challenge response), it also gives me a choice to add files into my password entry

I just use Proton Pass because of its easier access to email aliasing and occasionally sharing of sensitive data by sharing them a separate vault