Anyone is there to help me pull product stock via GAS

Google SpreadSheet is used, and I import a Veeqo product csv and use the csv header(sku, cost_price, qty) in Sheet1

I would like to use GAS (Google Apps Script) to pull into Sheet1
I need some guidance how to use auth and write the GAS code.

Is there a fully operational GAS to retrieve sku, cost price, and quantity? Is any developer willing to write a code for me? Please let me know.

I’m happy to pay if you require a fee.