React is a terrible idea. Everything about it is garbage. The api. State. How they do rendering. The “vdom”. It’s unnecessarily complicated and Byzantine. Like it was designed by someone trying to bill a large company many hours.
Svelte is ok. It could have been great but the api for their version of observables is a disaster (which I hope they eventually fix). Sveltekit is half baked and convoluted and I strongly advise not touching it.
React is a good idea compared to having to do SPA's without it. Try doing a SPA with only jQuery.
VDOM is also a good idea that simplifies the mental model tremendously. Of course these days we can do better than a VDOM. Svelte in fact doesn't use a VDOM. You can say that VDOM is a terrible idea in comparison with Svelte, but that's just anachronistic.
Svelte is ok. It could have been great but the api for their version of observables is a disaster (which I hope they eventually fix). Sveltekit is half baked and convoluted and I strongly advise not touching it.