For Modals specifically, I tend to make layer styles for the modal (container) and overlay (background). Depending on if they're themed i'll typically name them something like theme/dark/modal/container or something like that.

Then I keep the components within the modal as symbols and text styles (you might have headlines and descriptions in some or just headlines in others).

I found this to work best because you get the benefits of the design system without having to "Detach from symbol" all the time.