How can I track inventory for product variants effectively?

My products are all handmade at the time they’re ordered. I have 3 variant options (for how the product is finished); I use the same raw materials to make the different variants.

If I say I have 2 in stock, that means I have a total of 2 available (not 2 of each variant).

It seems that I can’t track inventory at the parent level - I have to choose to track by the variant.

Is there a workaround?