End user data entry for calculation

Hello, I am trying to find a way to build report like this:

I am connected to sql database from where I have generated list of products. I need the end user to fill the sale quantity for each product for each month so I can calculate the company's costs and profit. 

The problem that I can't solve is that the product list from database can change so I can't make a static list for end user to fill. 

I know a little about what-if parameters but I don't see this as a way because of the product list dynamic change and big amount of products. 

I have heard about power apps which would be perfect for filling the sale quantity. But I am not able to find a way to get these data from data app back to power bi where it could be used for calculation.

How could I make this work?

Thank you for advice.