Some additions:
1. In your case you should exchange "first" with "eq(" (oh, this editor: eq(eight) to address the desired row.
 

Your script - the one with "const noneRowIndex = 8" looks a bit strange. And now it is obsolete

2. if($('#movenextbtn, #movesubmitbtn').
Since LS Version 3 - when LimeSurvey was based on bootstrap - the ID is "ls-button-submit"

3. I doubt that this will work
if(($('input:radio[value!=""]:checked', this).length > ...
You address radio buttons, but your array contains checkboxes. Originally this script was meant for "normal" arrays.