Hi Anh,
WHen the built in doesn't work, customize! You can pretty easily make your own rating system using a Custom Module Class that has a integer "SkuID" that references the SKU class.
You may need to create a custom web part to handle new review submissions and ratings to utilize this, but it shouldn't be too hard.
https://docs.kentico.com/k10/custom-development/creating-custom-modules
https://docs.kentico.com/k10/custom-development/creating-custom-modules/setting-the-type-information-for-module-classes
Kentico makes it pretty easy, even generates the API code for you once you properly configure it, leaving only a little Type info configuration for you to do.