Agreed. I have a CMS project that uses both, but they are separated -- The CMS is a React front-end, with a node back-end. The sites maintained by that app are built by Astro via spawning a 'npm run build' in a separate Astro project that reads the CMS data, then writes the output to another directory from which I can deploy.

They do complement each other nicely... but there is little benefit to actually mixing them directly together.