I'm not sure if I got this correctly, but it seems like you're misunderstanding what Vite actually is or does.
For having built what is essentially a bundler, I would've guessed you were more familiar with what it does, or, perhaps even have used it to build your tool.
Vite can bundle framework-less html files. It can create an SPA without any JS faff. You just have to point it to the right direction. When you instantiate a Vite app, you have to make the conscious decision to use React under the hood.
As for Nue, I think it's a cool idea, but I don't see what it does that I couldn't do with Astro, which has way larger community support and can work with pretty much all JS frameworks OOB.
BTW, I think it's really disingenuous to compare a React SPA bundle with an SSG output. You have essentially no functionality for handling state mutations beside events. You could achieve a much better middle ground by using a compiled framework like Svelte or Solid.
