There is a property called 'excludedCategoryIds' in CategoryTreeService component. If you specify your 'Commerce Root' category id to 'excludedCategoryIds' property, then you will get your required hierarchy as follows, you will not get 'Commerce Root'.
product.category: Womens > Sweaters > Cardigans
Please let me know once if it works.
Thanks and Regards,
We are facing the same issue in one of the environments with the same code & configurations deployed. We are on ATG10.1.1 which doesn't have the "excludedCategoryIds" property. Any idea where this is configured in the ATG10.1.1