Slots: I want to be able to set variants as a preferred instance

I would like for Figma to support setting variants as preferred instances within a slot. Right now, it seems slots can only support base level components as a slot value, but our design system is currently composed of many variants.

For example, I want to build a card that can have different layouts of buttons at the bottom. In our design system, we have buttons in small, medium, and large variants, but I want the card to only allow for medium and large buttons. Ideally, I would set the medium and large variants as the preferred instances, but since Figma doesn’t allow a variant to be inserted into a slot as a preferred instance, the only way to achieve this is to rebuild the variants each as their own base level component.