Looks like the root of the problem is data is structured in different ways between primary and secondary data source:
Note how the primary source has many rows per project, where the combinations of Category/Subcategory are breaking down the measures, making the table taller. On the secondary data source you have a single row per project, and the column headers are breaking down a single measure, making the table wider. If you Pivot Data from Columns to Rows blending then works almost out of the box (almost because we still had to rename a subcategory per your original calculated field).
See attached for a working solution, I'd focus on the sheet called 'Pivot Fields'.
I didn't realize the structure of the data was the problem until later so my first try was to Create a View (Sheet) Selector for Your Dashboard , which I've done on the 'Sheet Selector' dashboards. I've left it for reference.
Hope this helps!
Sample Data set Workbook.twbx 72.1 KB
I'm having Tableau Desktop version 10.4 and 10.5.
Receiving below errors when trying to open your attached file.
"Errors occurred while trying to load the workbook "C:\Users\PLS5079\Downloads\Sample Data set Workbook.twbx". The load was not able to complete successfully."
"This file was created by a newer version of Tableau. Please upgrade Tableau to the version (or greater) that the file was saved in."