how to model category->product->variant tables in my multivendor marketplace database

Question

i have the following tables in my mind for my product database, but i'm not sure how to design them according to this structure: category->product->variant by the way, the prices change per each item, component, service, fabric and the vendor.

1. item group : upper body, lower body, full body
2. item : jacket, skirt, dress
3. item VS item group : jacket -> upper body, skirt -> lower body, dress -> full body
4. component : bust, hem
5. component VS item : bust -> jacket, dress, hem -> skirt, dress
6. service group : fixing, down-sizing, up-sizing
7. service : zipper works, narrowing, lengthening
8. service VS s.group : zipper works -> fixing, narrowing -> down-sizing, lengthening -> up-sizing
9. component VS service: bust -> zipper works, narrowing, lengthening, hem -> narrowing, lengthening
10. fabric : cotton, leather
11. fabric VS item : cotton -> jacket, skirt, dress, leather -> jacket, skirt, dress

i tried the following, but then one of my friends told me that i have to define all sellable products/services as 'variants', which made me so confused..

• category : item group
• subcategory-1 : item
• subcategory-2 : component
• subcategory-3 : service group
• product : service
• variant : fabric
• join/subcategory-1 & 2 : component VS item
• join/subcategory-2 & product: component VS service
• join/subcategory-1 & variant: fabric VS item
• other joins are solved by foreign keys