It seems like perfect simplicity built on time-tested cryptography: store pgp-encrypted files in a git repository. We already had an internal git server and used PGP internally, it was the perfect marriage. The tool provides the common functions like selecting which colleagues to encrypt for, finding an entry and copying it to clipboard... but think of the moment your organization changes. Everyone has access to everything offline, which is great if you need it in a rainforest or when the server is down, but also you'd need to rotate all exposed-to-them entries whenever someone leaves. Re-encrypting everything to remove an old key is pointless because the git history will provide an attacker with whatever version they need.
Offline access is useful for selected credentials (like the disk unlock password for some central servers) but, to avoid unnecessary rotations, should not be the default unless you're a sysadmin mentioned on disaster recovery team
Skimming the recommendations, so far there are no tools mentioned that don't require maintaining another service or that can't read your data. At least pass had that going for it