Work but with some limitations and bugs

Until plugin version 2.1.5, it worked (loading its form in front-end checkout) only with WordPress version 5.4.6 (tested by myself downgrading from 5.7.2, running Woocommerce 4.9.2).
With actual plugin version 2.2.0, works with WordPress 5.8 and Woocommerce 5.6 (latests).

There is a limitation (IMHO) consisting in the behaviour of the plugin, wich is that the shipping methods and fees will be loaded on checkout form only after the customer enters and address.

I have also founded 2 bugs:

• When order amount is discounted by a coupon/discount code, shipment fees are not applied correctly. The application of free shipping over amount ruled by the UPS plugin does not take into consideration the discounted order amount but only the non-discounted subtotal.
  So if you offer on your store free shipping over order amount AND discount codes, know that

1. if the non-discounted subtotal is over the the minimum required for free shipping
2. if the resultant discounted order amount will be minor than the minimum required for free shipping

free shipping will trigger anyway (and that will be a problem for you).

• If a customer both selects an Access Point as delivery location AND fills in the Shipping address fields, the value in the shipping address fields will OVERWRITE the delivery address in order form, but not in the plugin’s back-end section dedicated to label printing.
  So you will have

1. the order form with a delivery address (filled by customer)
2. the label for ship the order’s product with another delivery address (the Access Point’s one)