you could distribute mini-apps as binaries linked from simple web pages :)
there's also a growing set of mini-js frameworks that are built to be enhanced by backends that might be interesting to explore
* htmx https://htmx.org/
* htmx without htmx https://dev.to/zkat/i-replaced-htmx-with-a-simple-web-component-4bnh
* https://data-star.dev/