A password manager like bitwarden but distributed that would work in p2p to synchronize the encrypted database.
This way we don’t need to install bitwarden on a server or use third party cloud applications (nextcloud) to synchronize the keepass database between our different devices
Syncthing is capable but not perfect at this. If you edit your password file on device A then edit the file on device B, without syncing in between, Syncthing will have a conflict and you might lose data. Ideally you want the password manager to handle syncing so it can do it at the entry level.