"Export To File for Power BI Reports" - Getting NotFound and FeatureNotAvailableError

Thanks for providing such a detailed breakdown of your setup and the steps you've already taken it's clear you've done a thorough job troubleshooting this issue. Based on the symptoms you're describing specifically the "NotFound" and "FeatureNotAvailableError" messages it seems likely this could be related to known limitations of the Export to File for Power BI Reports action when using Premium Per User (PPU) workspaces.

While PPU supports many features of Power BI, the export API sometimes enforces stricter licensing requirements, especially if the tenant settings or capacity assignment isn't fully aligned. One thing you might want to double-check is whether the Export to File API feature is enabled in the Power BI admin portal for your tenant.

Additionally, make sure that the workspace is not only marked as PPU but also fully assigned to a PPU capacity, as certain backend processes may still rely on capacity association. If everything appears correct and the issue persists, it might be worth opening a support ticket with Microsoft, as this could be an edge case or a backend configuration issue. You're definitely not alone others have run into similar issues with the API on PPU setups.