As I said, make it fully self-contained without relying on "builds" or any other mumbo-jumbo, the way you would with sphinx or hugo or whatever. Essentially add a new html or markdown file, put whatever you want in it, let's call it "something.md". Then add a link from your index page to "#/something.md" and not deal with builds or styling or whatever, simply commit and move on and have it take care of all the html. And in the case of markdown, parse it and render it as html on the client.

Does Algernon fit the bill? https://github.com/xyproto/algernon

Quoting their README:

Web server with built-in support for QUIC, HTTP/2, Lua, Markdown, Pongo2, HyperApp, Amber, Sass(SCSS), GCSS, JSX, BoltDB (built-in, stores the database in a file, like SQLite), Redis, PostgreSQL, MariaDB/MySQL, rate limiting, graceful shutdown, plugins, users and permissions.

All in one small self-contained executable.

I searched for something similar. Considered Caddy and Nginx/Apache with markdown plugins, but wanted to be able to create and edit pages/files and made a small script with Flask instead.