There are a few ways to debug it.
Check in administrator role that Import/Export is not un-selected.
Can you create a new user using command bin/magento admin:user:create and login to admin panel using these newly created credentials to check if you can see Import/Exports.
Disable all the custom modules one-by-one to figure out which module is causing issue....
You're asking how to run PHP inside a client-side rendered file which is not feasible. I believe you would need to build this yourself from scratch.
The template is set in vendor/magento/module-checkout/view/frontend/layout/default.xml
<item name="template" xsi:type="string">Magento_Checkout/minicart/content</item>
As you can ...
I was looking for the same thing, but only found paid modules that required a monthly service fee. Ended up having this module made from an old magento v1 exention that is no longer supported. Try this module. It works with Magento v2 and adds the option to get UPS LTL Freight Shipping.