As I mentioned before, view libraries start to adopt Signals to improve performance and DX.
However, not all of them do that. My personal opinion is that React is no good in 2023 because of this, it is moving in the wrong direction, and bringing NextJS down with it (which has it’s problems too, to be fair).

So, what would I choose for SPA?

• Preact (maybe), Vue, SolidJS, Svelte

Preact is in a maybe territory due to the fact that it seems like it is not moving at the same speed like other libraries.
I would try it out for small apps and see how well it works. And there isn’t really an SSR route to follow, if the app gets bigger.

What would I choose for SSR?

• Nuxt, SvelteKit, SolidStart

I would really like to use NextJS with Signals (or basically with Preact), but that would be a rough journey.
And NextJS is making something weird with pages->apps breaking change, and I am not sure about that.