FormulaMap for creating multiple rows

Hey @Paul_Danyliuk :wave: hope all good?
I am not sure if my problem is solved already with this post, what I am trying to do is to propagate a new table with 2 columns; one with one value and the other with 1-n values

Finally I want to have this result (for each region and category one row)

This formula is not working:
r_region.FormulaMap(AddOrModifyRows(r_category,Region=Region and Category=CurrentValue.Category,Region=Region,Category=CurrentValue.Category))

Any suggestions?