You need to enable an option in the portal extension that allows you to create a shareable view where users bypass the login page and see the shared view directly. To find it, go to:
Users Table.
Turn off Require users to login to use portal toggle
Set Record ID for Skip login with default user record ID
This configuration will turn your "portal" into a sharable/editable Airtable View. It will show all the records from the table regardless if it is connected to the default user record ID or not.