https://shopify.dev/docs/api/admin-rest/2024-07/resources/carrierservice
It states: Using the CarrierService resource, you can add a carrier service to a shop and then provide a list of applicable shipping rates at checkout. You can even use the cart data to adjust shipping rates and offer shipping discounts based on what is in the customer’s cart
I know how to do shipping discounts, but where are the (which api calls) functions for adjusting shipping rates using cart data?