How to add multiple countries/carriers/weights shipping methods easier?

[rockayshop]

Hi! We ship from one warehouse to almost a hundred countries using half a dozen carriers.

Some countries support all carriers and have a division of prices based on weight: 0-100, 100-500, 500-1000 grams etc.

Also, we have free shipping conditions.

We want to charge our customers the exact shipping price and to show it on checkout before they pay.

Based on Shopify functionality and our app - Shipmondo, we have to add each country/carrier/weight/price combination manually. That is hundreds and maybe even thousands of combinations. It is an insane amount of work. And what if some carriers increase prices by 15%? It would take weeks to make updates.

So the question is: is there any easier/faster way to make Shopify show custom shipping rates for all these conditions we have?

We used to work with Woocommerce and there we simply had a sheet that was parsed into the database and used by Woocommerce to show rates on checkout and charge them.

Is there anything like that in Shopify to upload multiple rates via sheet or something similar?