You are wrong, I have built several search forms that do exactly that and work perfectly, they allow you to search for products and to refine by product categories, and by product tags, and if you add the other plugin I mentioned , it also allows you to search by acf custom fields added to the products.
if you are interested in learning how it is done, check out the video on youtube called:
“Create an Advanced Search Form With Avada Forms”
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