Unified SKU for One-Time Purchase Bundles

I currently offer bundles on the same product page, allowing customers to choose a subscription or buy 1, 2, or 3 pouches as a one-time purchase. However, the one-time bundles are set up as variants, which isn’t ideal because each bundle acts as a separate SKU. This means stock isn’t synced, and I have to manually update inventory across all variants every day. It would be beneficial to have a feature that allows creating a selling plan that lets customers choose 1, 2, or 3 pouches as a one-time purchase, all pulling from the same base SKU.