Massive decline in performance since optimizing for purchases?

I know that from an ROAS perspective we don’t care about anything other than purchase conversions. That said, switching to a purchase conversion when fb suggested we would get zero conversions has truly resulted in zero purchase conversions and no improvement across any metrics higher up the funnel as we saw with previous campaigns higher up the funnel. We’ve spent about $1000 so far, around $300 on a purchase campaign.

Is it worth just killing ads all together? Just not sure where to go from here since hearing that optimizing for anything higher up the funnel will lead to just clicks and not much else (which is all purchases did for us but without any ATCs or any other conversions)