Shopify to QuickBooks Online

I am trying to get a better functionality with Shopify orders to QuickBooks invoicing. All the apps that support syncing, will not sync remove line items from a Shopify order to a QuickBooks Online invoice. It will add items, or edit fulfilled quantities.

Does anyone have any tips or advice on how to add this custom integration?

We are looking at this now, why do you want to not use the standard quickbook app?