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You can set quantity available for each product using the inventory widget.
So if you set only 1 Qty for each product, that item/product will only be available on your form once.
Let us know this workaround will not work for you.
Another option is to use Unique question feature.
What it does is, it makes each of the items/options unique. So they will not be selectable more than 1x on the form.