If you're into this sort of thing you should look into Marko. They're kind of obsessed about page load perf with the justification that it's good for e-commerce

If you're into this sort of thing you should look into Marko. They're kind of obsessed about page load perf with the justification that it's good for e-commerce. They've also been into streaming, partial hydration, out of order rendering, etc for years as part of that general effort.