Require Postcode field in Cart Shipping Calculator

I apologize for the duplicate thread post. However, my original post was incorrectly marked as “Resolved” as an answer to a question I wasn’t asking.

To avoid the confusion in my original post, I’d like to clarify that I am not trying to report a bug or an idea. I am simply asking for assistance customizing my own personal instance. With that said, here is my question:

I am trying to force shipping estimate to use postcode and country. Only country seems to be required by default, and postcode is optional with the field even greyed. Here is an example image of Change Address fields. How do I require both country and postcode? Note – State and city are not required for my use case.

In short and to clarify, I am asking how I can customize only my instance of WooCommerce to make postcode field required in the cart shipping estimator?

Thanks.