somehow people have accepted the idea that writing software to render mostly text documents must be a gargantuan job, which only a handful of companies can do.
Rendering a small but useful subset of the HTML spec is a reasonable job for a single individual and it is not so crazy to do from scratch. You can also take a look at Gemini (not the garbage from Google).
Write simple websites that can be rendered by simple browsers. This is perhaps the hardest part.