But I need it show me all line items that are unfulfilled and qauntity is <= the quantity available

comfortable with engineering summary criteria? if not, LMK and I'll post an example

don't think you can get away with doing this without resorting to a summary search

You're in an interesting situation with only one location, so you can use

item.quantityavaiable

. If you were using multiple locations, you then have to use

item.locationquantityavailable

and then add a standard criteria for

{location} = {item.inventorylocation}

to tie the sales order line's location to the item location.

goes without saying that summary criteria only work as intended with summary results. In your case you'll want to be grouped by sales order. If you need a list of item info in your summary results, you can leverage

LISTAGG