Hi there, HAM9000_8.

I appreciate you for sharing your thoughts about adding a discount on every item created in QuickBooks.

For now, there's currently no feature to add a discount field in every line item. I see how this option would be helpful for you and your business. 

We are looking for ideas to improve QuickBooks Online. With that, I would suggest checking our blog website in your free time. From there, you'll be informed if adding the discount field in every line item will be included as one of the release features in the Online product.

And, yes, you're right that creating a service item is fine for the discounted rate. Then, manually add it as a line item on the customer's invoice or credit note. In your case, you may assign your discount account in the Income account field by creating a non-stock item, as suggested by my colleague JessT.

If you have other questions, please post them. I'll make sure to provide you the information you'll have to know. I hope you're good. Stay healthy!