Ubercart to Commerce Migration – Just migrate users/orders?

I’m having a heck of a time trying to migrate my D7-Ubercart site to D8-Commerce. Attempting to use the modules, drush, etc, has simply resulted in days of errors and roadblocks.

I could easily do all the products etc via feeds, but the remaining issue is my some 40,000 orders/customers I need to migrate over from Ubercart. I don’t see any way to do this stand-alone unless I am missing something? Any tips or info would be greatly appreciated.