How to authenticate users in Zendesk based on being logged into our SAAS platform so we private knoweldgebase articles to be suggested to users only when they are logged into our platform

Our organization provides a SAAS platform for employers to provide benefits to their employees. We want to build out our knowledge base so we can leveraged AI Agents, Message (chat) bots, and other AI tools. We want to ensure that users outside of our platform cannot see these articles but we do not want to have the users take an additional step to log into Zendesk to see the articles. Additionally, we do not want any random person to be able to create a Zendesk Guide account to be able to view our articles that would be protected behind the login. 

How can we connect our own database to authenticate if a user is logged into our platform to both provide them access to the private knowledge base articles and not have them have to log into Zendesk on their end to view them. 

Additionally, we want to connect our user database to zendesk so we can auto-populate user profiles in Zendesk, can you provide the article for this?