I have to say Svelte is my first thought, even though it explicitly misses some of the criteria. There's a lot of criteria in the original question, which will

I have to say Svelte is my first thought, even though it explicitly misses some of the criteria. There's a lot of criteria in the original question, which will inexorably lead you to React. But for learning fast from scratch and doing lots of iteration and rewrites on a very complex UI, Svelte is going to provide a leg up. The biggest issue is finding a UI library you are happy with, and dealing with inevitable Sveltekit changes. I used tailwind and it integrates ok with Svelte. And I've just resigned myself to dealing with Sveltekit updates.