Excel Use of External Source Data (not import)

Hello.

I'm using Excel to do analysis on sales data at the item level.  I'm trying to find a way to do this using Excel but not have Excel move too slow because of the amount of data in the worksheet.  I'm wondering if there is a way for Excel to access and use external source data "without" actually importing the data.

If not, would it be better to have an Excel workbook do the custom importing of external source data and use a separate workbook to access this data.

I have imported data in Access and Power BI but I cannot create the data analysis that I want with those programs.  So I'm trying to figure the best options.

Thanks in advance for any ideas you may have.

Scott