My plugin allows you to create wholesale orders from the backend, through the Orders page using the “New Order” function already built-in to WooCommerce. Through that, you can select the customer, and then the prices will be based on if that customer is wholesale or retail.
My plugin does NOT, however, offer any kind of order import functions. You could most likely use any CSV Import plugin that imports WooCommerce orders, and then just map the extra meta fields and order terms that my plugin uses to mark it as a wholesale order. Something like WP All Import allows you to map custom meta, but I haven’t tried using it to create orders, so not sure how it would work:
https://www.wpallimport.com/import-woocommerce-orders/
If you wish to discuss a custom option that would speed up your process and make your life easier, you can email me privately. But, I don’t currently offer any integration with things like Zapier or Integromat or Google Sheets.