Astro is a meta-framework that allows you to plug in other web frameworks where you need it (React, Solid, etc). Although it would also be fair to consider Astro a sort of build tool / bundler.
Node is a runtime, not a framework.
So there's really only one framework here (Astro). Using other web frameworks within it is completely optional.
"Astro supports every major UI framework. Bring your existing components and take advantage of Astro's optimized client build performance."
But isn't Astro a framework itself? And then apparently you need Node as well. The frameworks upon frameworks in Web development are baffling.