This is where I've found Astro to really shine. Most people reached for it because of the whole "islands of interactivity" concept, but IMO the ability to easily build a mostly static site with server APIs when needed is a the killer feature.
I manage multiple Astro sites and eventually they have all needed at least a few small server endpoints. Doing that with Astro is very simple and it can be done without making the static portions of the site a pain to maintain.
Just a small note - I see a lot of warnings about "Long Tasks" in the dev console log (Chromium) - likely related to the animation which is jittering on my Mac M1.
I manage multiple Astro sites and eventually they have all needed at least a few small server endpoints. Doing that with Astro is very simple and it can be done without making the static portions of the site a pain to maintain.