Click on Manage rates for whichever shipping rates i.e. (General, Custom) you have configured. In our case, we have configured Custom Shipping rates.
Delete your preferred shipping rates OR an entire zone, further hit the Save button.
If you have turned-on both Amazon's real-time shipping speeds as well as Shopify shipping rates, then at order checkout, for a similar shipping method (with similar values like shipping fees, order total, etc.), either a Shopify shipping rate will be displayed OR an Amazon's real-time shipping speed, so it is requested to turn-on either of those, not both, as Shopify will give preference to its own shipping rate, further your customers won't be able to see Amazon's real-time shipping speeds.
In case, you have any questions OR want some assistance, feel free to reach out to us at email@example.com