Is there a way to constrain proportions of variants, so when instantiated you can set them to Fill the parent container without loosing the original aspect ratio?

Hello Figma world,
I’m making a video player component in Figma with a few variants for aspect ratios. I want users to be able to “Fill” their parent layout both Horizontally and vertically while preserving the proportions of the variant they have selected. In other words I want to lock the proportions of my variants.

I’m finding that it’s easy using contraints on basic frames but that both the “lock aspect ratio” and “Constraints” features are unavailable when working with instances and variants. So what can I do as a workaround?

Thank you kindly for any help with this.