I you would have shared a dummy copy of your problem, I could have worked in that.
See below what I created, we count the number of items in the list and create as many rows as we count items (4 in the first row, 2 in the second row).
the button code
Sequence(1,thisRow.[list with items].split(",").Count()).FormulaMap(To.Addrow(To.ID,thisRow.ID,To.[numbers per row],thisRow.[list with items].Split(",").Nth(CurrentValue)))
hope it helps, best, Christiaan