Cannot find custom taxonomy in attribute list

We have a custom taxonomy (Make/Model) via CPT UI set to Products Post Type. We are able to assign Make/Model to each product and have other filtering systems using this taxonomy that work fine. But when trying to create a filter, selecting Attribute, and then under Select Attribute, the only things that show up are Color and “Custom meta field Pro”. The Makes/Models taxonomy doesn’t show up. Any ideas why?

The page I need help with: [log in to see the link]