UPS real time rates with Amazon? Customer shipping rates

Hi- I can’t find this info anywhere. This pertains to the Shipping Templates which dictate what customers are charged for shipping rates. Any other platform uses a integration for UPS Realtime rates, Amazon for some reason wants us to fill out these Shipping rate Templates which is right out of the late 1990s. Needless to say this creates a ton of work for what seems like no reason, not to mention allow room for error. Am I missing something?

Our negotiated rates don’t directly import into the shipping templates, not to mention items ship in their own boxes so I’d have about 100 different box entries I’d have to account for.

Is there an easy/automated way to get customers their shipping rates? Why doesn’t amazon just take the product box size and ping UPS for a rate?