I searched everything and couldn't find an issue related to my problem.
Most of our product attributes are hard coded in a way that they don't exist in Products->Attributes but are directly created inside the products with a pipeline separator (|). I tried a few filtering plugins but none of them seems to be able to discover them so I guess I need a custom solution.
The only thing that comes to my mind is looping through all the products to show the filter and a WP query with specific attribute parameters to filter products. Since we have thousands of products, I worry that this could be slow.
Can someone guide me if this is a good approach or is there a database table or something that stores hardcoded attribute data that can be better utilized to make a solution for this?
Or...Is it a better option to create the attributes in Products->Attributes and recreate all the products?