I must have missed the fact that you wanted to use this with a acf_form().
There isn’t any way that I know of to only show one row of a repeater field on a front end form. You can specify which fields you want to display but that’s as far as it goes. The front end form would show all the rows.
If you wanted to use the with a front end form you’d need to create a separate field group for the front end form and then use the acf/pre_save_post action to update the repeater field with the new row.
