Dashboard user management

Hello,
I am facing a challenge with managing dashboard users when SSO is enabled.
The use case is a Contact Center environment, where I have a list of users who are meant to have access to the dashboard. Each user has a set of attributes used for dashboard data restriction and filtering.

Not all agents have a login to Qualtrics, therefore their username does not exist as a platform user. Nevertheless, we need to manage this list to make sure that when they do log in the attribute is available.

The other part of my challenge is that the username is an SSO attribute (UPN) which gets appended the #brand tag. Unfortunately, the client is unable to export the list of UPN (usernames) to include in the user import at the dashboard. This means that Qualtrics will use email as the primary identifier for the user and because in most cases email does not match UPN, then we have a mismatch where users are being created as new users.

The workaround that I have is that periodically I do an extract of the users in the platform, run a lookup against the list of dashboard users to make sure that I only import users which have previously login to the platform. 

This is very time consuming and not scalable. 

Is there anything that we could try to do to simplify this process?

Thank you