I don’t know a way to create parametric hearts on sketchup, actually modeling with quads and subdividing the geometry is in my opinion the easiest way to do it and also the one that delivers the best results, it could take a bit of time to learn and get used to modeling using quads, but once you get it you can model absolutely anything you can imagine, I’ve modeled cars, human characters, really complex buildings like the Heydar Aliyev Center and tons of things more using this method.
Here are some examples of what I’ve done. Made in Sketchup by me and myself