How to offer a discount for purchasing 2 units — for non-business customers?

I have been selling a product ASIN B09DSBGMGF and now I would like to offer non-business customers the option to purchase 2 of the exact same product at a discount.

Does anyone know the right way to do this (no guessing please)?

Here is some more info ...

- I know there is an easy way to set this up for business customers, but I want to offer it to all customers.

- I don't want to have to create a new UPC or anything like that because it is the exact same product, just quantity 2. So there is no reason to need separate bar codes or different inventory or anything else like that. For clarity, this is NOT a multipack or bundle.

- Variations seem to be the way Amazon may want to do this, but there is all sorts of ambiguity with this, particularly since the product I have is already being sold and variations require the Parent SKU to be non-sellable. I don't want to risk "breaking" that product and losing sales.

- I have already tried editing the product listing and using the VARIATIONS tab to add a variation but I get an error and Seller Supports has confirmed it is a bug with no indication if it will ever get fixed.

- I've read through everything and found people asking the same question in the forums but no clear answers, so I thought I would give it another shot here.

Thanks for any help with this.