Keycloak/Authentiq SSO/0auth support CE


In the community edition , is there an option to enable SSO with other selfhosted opensource software such as keycloak or authentiq?

I am not interested in cloud services , hence looking into Passbolt and i was wondering if i could get this feature somehow. I know there is a pro version that does Google SSO but im looking for only self hosted software.

Also if the pro version supports this , is there a lifetime, one off license option instead of the monthly one ?