A static site generator (similar to hugo et al.) whose sites can be built in any of the big web frameworks (react, vue, angular, svelte, or -- they claim -- any other for that matter).

It also boils everything down to plain html but let's you embed javascript components if you wish,
and those components will only be loaded if the user actually scolls to them ('island design').

Sounds very promising, currently in early beta.

SImple blog tutorial here:
https://www.rockyourcode.com/build-faster-websites-with-less-javascript-using-astro-tutorial/