You can do this easily using Insert/ Delete Rows activity to add a row in a particular location. It will move the rest of the rows below downwards. Since you are doing this in a loop, just add one row at a time, and specify the excel row index where you want to add the row. After this activity, we can use a Write Cell activity to write the cell value. We do not need to write an entire row in your case.
I have modified the workflow you shared to get this done. Check it out…
insert rc value.xaml (7.9 KB)
Just change these properties according to the place you want to add the row and write the new data.
For Inserting row:
For Wring data to cell:
Edit: Please add this tick to your Excel Application Scope to save the excel file after this change
If this works for you, please also make sure to mark the answer as the solution too