Auth issues - Invoice Data API with Microsoft Fabric / Power BI

We are planning to connect the Invoice Data API (Version 2.6) to our Microsoft Fabric / Power BI to create automated reports.

However, we are currently facing an issue with authentication:

According to the API documentation, a user's email address and password are required to create the access_token.

However, our organization exclusively uses Google SSO (Single Sign-On) for the Candis login.

Our assumption is, therefore, that our users do not have dedicated Candis passwords that we could use for this "Password Grant" flow.

We have a ClientID and Client Secret, but we were unable to successfully implement the flow described in the documentation (which requires an email/password) with them.

What is the correct authentication flow for the API when the organization uses Google SSO?

Is there an alternative mechanism (e.g., using the ClientID / Client Secret via a Client Credentials Flow or a dedicated service user) that does not require an individual user password?

Or are we overlooking a way for SSO users to generate an API password?