We have many users who are portal-only customers, and they are required to log in to our Jira Service Desk to log tickets. I want them to be able to search for and find knowledge base articles to for greater self-service, deflect tickets, and reduce the time we need to bounce tickets back to the portal-only customer.
I've created a Confluence space, written a couple of articles, categorized them, and linked it successfully in Service Desk. I've enabled anonymous access in global permissions in Confluence, I've enabled anonymous view access to Confluence in the space settings. In short, I've followed all the documentation on linking Jira Service Management and Confluence together.
When I log in with a licensed seat, I see the articles from the help portal:

When I log in with a portal only customer, I do not see the articles:

I can use private browsing to see the entire Confluence space without requiring authentication. I can read the articles I published, so I think guests have sufficient access to the space and articles:

How do I enable guests to see the articles in the Jira Service Management portal?