After a few years of dabbling with Flutter I just came back to the same conclusion: bet on HTML.
Astro / Tailwind / Daisy UI / Alpine.js makes it lovely to build an HTML site with a lot of simple SSR and a little bit of client side reactivity peppered about.
The result is simple sane HTML files that look and work great on desktop web browser and and mobile wrapped web view.
My app is basically static so it caches in a CDN, works offline, and view source makes it easy to debug.