Bitwarden is not offline by default - it stores you passwords in the cloud and keeps a local copy. So you can access it offline but you need online access to edit it. See: https://www.reddit.com/r/Bitwarden/comments/9yv32e/can_bitwa...
Keepass is nice, it's what I used before Bitwarden. It's not great at syncing across devices or sharing passwords with others, though.