Direct Query unable to process more than 1 Million records

Hi Team ,

I have a requirement to be incorporated in Power BI .

There are 3 Millions records for one date. We tried using Direct query to create a Power BI visual , but the response time of a specific visual is 1.5 Minutes which never be accpeted. In our dimension we have Country and Measure is Simple Sum(Sales) it is a normal bar chart.

We have 150 dates in all . Please help us know if direct query is not the appropriate in such scenarios.

We also tried using import mode and the refresh takes around 14 hours to bring in all 150 dates ( This option is also ruled out) 

We tried Incremental load , but eventually the PBIX file size reaches 20 GB and eventually does not open up in power BI service as we append recent data everyday.

Any suggestions will be helpful.

Thanks!