I’ve seen the interest in using “slots” in Figma grow considerably lately. Although I understand the utility of building components this way for flexibility, those of us Designers who have worked with game engines like Unreal Engine or Unity are familiar with the concept of modified instances of “prefabs” (analogous to components), which will accept new objects into the instance while preserving the link to the parent object as expected. Resetting the prefab will also destroy any of these “foreign” objects which have been inserted into a specific instance. You can even create a new prefab parent object from a modified version of an existing prefab!
I’d love to see this functionality injected into Figma as it would be infinitely more easy to modify instances and maintain flexibility without destroying your source of truth, or creating too many variants.