Hi, I know this is an old post, but I thought my answer might be useful to other users looking for help on this.
The way I found to achieve what you want is:
in the Topic and the Decision cell, create a content-controlled Rich Text or Plain Text box.
Select these boxes, and in their properties, tick the box "The content control cannot be deleted". Now select the whole row of the table you want to repeat and click on Repeat Selection Content Control. Now you can fill in the content control text boxes within the table, but when you create a new row, it will appear with new content control boxes that are empty.
At least that's how it works in my Word 365.