"In Power BI PPU, Dataflow Gen 1 does not support direct query.

Hi lavendar ,

Thank you for your response, and I appreciate KNP  for offering clear answers.

Performance issues with Gen1 dataflows, even with ECE enabled, are uncommon and often mean some query steps aren't folding as expected. It's a good idea to use the Performance Analyzer in Power BI Desktop or check the dataflow refresh logs to see if Enhanced Compute Engine is being used effectively.

For slow "Close & Apply" times in Import mode, this is usually due to merge operations that aren't folding to the source, so processing happens locally. To improve performance, try moving merge logic into the dataflow or into a SQL view upstream. Gen1 doesn’t require explicit storage since it uses managed storage internally.

Your architecture, which avoids direct connections to the production SQL DB, is good. The slowness is likely related to specific transformation steps rather than the platform itself.

Hope this helps. Please reach out for further assistance.

Thank you.