Would anyone be able to suggest the best plugin for executing shipping rates based on zones? I'd love to see the ability to upload a CSV instead of manually entering hundreds of lines of rates across 5 different UPS services.

I see that there are a few:

NopDestek Table Rate Shipping Plugin
https://www.nopdestek.com/nopdestek-table-rate-shipping-plugin

Shipping by Zone and Weight ranges
https://www.nopcommerce.com/p/1597/shipping-by-zone-and-weight-ranges.aspx

Shipping Director - too complicated for me to use effectively and regularly.
https://www.noptools.com/p/34/shipping-director-for-nopcommerce-380