The site we're working on happens to have multiple style attributes for buttons — button color (2), button shape (2), and button size (standard/small), so there are eight variations. I will often need to use more than one of those in the same spot, but since there's no "swap symbol" function, any customization that I've done to the overrides (in this case, button text and link) have to be performed again even though all I'm trying to do is change the style of the button.

Just as it's done in Figma, and even in Webflow with images, you could easily add a "Swap Symbol" function to the contextual menu, bringing up the Symbols panel and letting you click on a replacment.