I would like to throw out Bitwarden out there. Cross platforms, works on everything and can be self hosted if you so desire.
bitwarden looks cool. what parts are open-source and what parts are closed? (are all the premium features closed-source or are they just charging for that in the hosted-by-them version?)
I see some of the newer premium features, particularly around SSO are under a noncommercial visible source license of their own devising though