Astro + Cloudflare Pages is pretty good. You can start with just a static site, fetch content from anywhere, including Markdown files or an API, and you can provide interactivity in islands.
What kind of full stack technologies do you use? In the JS world at least, these are all defined terms for at least some time now. The only new thing is islands, which is explained on the landing page in the section Introducing Astro Islands.
Sometimes content has terms of art, it is not their fault for assuming that the reader should know what certain common phrases and acronyms are. It's like being on Hacker News and having to have HN, YC and PG spelled out for readers; it's assumed being on HN that readers know what these are.
What the fuck is an island?
"Lazy loading islands" What?
"Components only hydrate when they scroll in to view" WHAT?
"Need interactive UI? Load individual, non-blocking component islands in parallel." WHAAAT!?
"...and live server output (SSR)" SSR = Live Server Output. OOOOOOOkay.
50 acronyms later and I'm way too fatigued to try this shit out.