Pls check the Pivot2D process, pipe the result to a datastore and print out the output to see its structure:

https://www.koolreport.com/docs/pivot/pivot2D_process/

Once you understand result of Pivot2D, you could apply a Map process to change the total row value to what you want:

https://www.koolreport.com/docs/processes/map/

If you have any difficulty let us know. Rgds,