Proton is a great company with a pretty good record, but I wouldn't recommend them for passwords when Bitwarden exists. Proton only open-sources their clients, and for service based offerings like mail or VPN I don't care about the servers being open-source, but for password management I want to be able to host my own (making sure that self-hosted mail gets properly received by Gmail is pain and self-hosting a huge VPN network is basically impossible).