Hello @armankazi111 and welcome to the community!
Since “Product Category” is a linked record, you can’t filter the product based on the field value of a linked record, this is a feature request that we are currently working on: Deep filtering on both CMA and CDA
For now, you can only filter linked records based on the numerical ID of the linked record (that is, you can only filter the productCategory based on the numerical ID of the productCategory record)