You installed a filter app because Shopify's native filtering wasn't showing the right options. The app costs $29/month. It looks better. The filters actually show up now.
But the filters still show inconsistent values. "Blue" and "blue" and "Navy Blue" all appear as separate options. Some products don't show up in filtered results at all. The app didn't fix the problem. It dressed it up.
The real problem
Shopify's native storefront filtering reads product metafields. If the metafield values are inconsistent — different casing, different naming conventions, missing values — the filters are inconsistent. No app can fix that. The app is a presentation layer. The data layer is yours to fix.
This is test content for template verification.
What grounded looks like
Flat product metafields with normalized values. Every color value lowercase. Every size value from a controlled list. Boolean fields for binary attributes. List fields where multiple values apply. Definition first, data second. When the data is grounded, native filtering just works.