There is, Datastar has client-side rendering based on signals [1]. Datastar is also very explicitly designed to be modular and extensible, so you can extend the client-side with more features, as they've done with Web Components.
Signals aren't even really "rendering". And react and spas dont have a monopoly on doing things on the client - that's just javascript. I dare you to go to the datastar discord and tell them that they're React-adjacent, and SPA-like
