Zapier - when item created, create subitem

I am trying to create a zap, which is triggered by an item being created in a board, and creates the (repeated) subitems for me. I know I can do that in Monday (and have) but our team wants the name of the item in the name of the subitem, and the only way I’ve found to do that is to use zapier. currently, if I use the item name where it asks for it in the ‘create subitem’ step, it returns this error: Variable item_id of type Int! was provided invalid value. If I use the item ID, it returns this error: To create a subitem you will need to open a “Subitems” column on the board you selected. The item I tested it on has subitems (18 of them) so it definitely has a ‘subitem’ column. Anyone know what is going wrong? i reached out to monday.com and they took a week to tell me they cant help, and i reached out to zapier who took a week to tell me to send a screenshot which i included in the original help request.