My self-hosted bitwarden server is only accessible from the LAN. Since the full password database is cached locally on each client, you can use it to lookup existing passwords just fine without a connection to the server. Bitwarden does require a connection to the server to add passwords, as it isn't a distributed architecture, so this setup does prevent you from adding new passwords while you are out and about, but I don't have the need to do that often, and in the rare occasions when I do, I write them on scrap paper in my wallet till I get home.
For home use, and to a limited extent - when all your users are proficient - for corporate use, I really enjoy pass (https://www.passwordstore.org/). It has a decentralized architecture where passwords are synchronized via git, making it excel at situations where you need to generate or store secrets on the go. Unfortunately, the Windows client is not stellar, and the (unofficial?) Android app doesn't seem to have an option to encrypt secrets using more than one key, limiting its use for most teams.
I got really excited about pass for a bit and almost switched to it, until I realized I was likely increasing my attack surface because in addition to trusting the developer of pass, I also had to trust the developer of whatever other third-party clients I was using with it (such as the iOS client).
