Unironically have been migrating my static pages (from Nextjs and Eleventy) to plain HTML and love it. Of course depends on your use case if that is feasible.
First, it doesn't have any provisions for code reuse. So, if you have multiple pages that use the same header, same footer, or same navigation menu, your options are either to copy-paste it (gross), or to build the final html out of smaller pieces, at which point you've reinvented either a static site generator or a web server.
Second, if you write long stretches of text, the html markup can get in the way, as opposed to unobtrusiveness of something like markdown.
I’m tired of the constant update pressure from existing solutions and I only need something dead simple.
It doesn't have to be Astro though. You can build something super simple that just includes the header, footer, and nav. Leaving most of the site as plain HTML.
Welcome to the 1990's web coding.
Then one is pretty much safe from framework tides.
There's one other I've seen recently that looked good but I have misplaced the link
There's even an article about it somewhere.
But why are you looking for alternatives already?
Disliked the templating solutions, the messy documentation, the loss in momentum, and liked a lot of the stuff (especially the tooling and principles) in astro.
Also strongly disliked how political eleventy got.
I just wanted a website, not a an internal debate about what I am potentially being absorbed into. I can vote, and spend money on donations, I don't need to enact change through my tech stack.