Below is a screenshot of my process.

The JavaScript code goes through each Shopify order line item & calculates a sum of the total number of items orders. (Output = {Sum})

I then loop through the rest of the process from 1 to Sum (num of items)

In this loop:

1. I query a Google Sheet to get all values in column A
2. Retrieve the last value in the column
3. Delete that value from the sheet
4. Create a Firestore document with the following fields:
   1. Buyer Name
   2. Buyer Email
   3. Buyer Address
   4. The retrieved value from the Google Sheet

This is the problem in a case study:

1. The new order has a total quantity of 4 items
2. 4 Documents are created in Firestore/Firebase
3. The first document has the correct retrieved value from the Google Sheet
4. Documents 2-4 all have the same retrieved value from the Google Sheet.  Different from the first, but the same from 2-4.
   1. It is as the Google sheet actions are only triggered one time.  The rest of the loop iterations just use the same retrieved value as document 2.