This is LVGL. https://lvgl.io

In the back, looks a lot like a simplified DOM. You could, literally, implement a DOM ontop of it, because all the basics are there and you'd just have to polyfill the rest.

Then feed LVGL the APIs to draw stuff (bring your own framework approach, essentially) and... that's that.

I love the idea and codebase of this project. Such a cool idea: Focus on one thing, and do it great. This is what it excels at. And, exactly why I want to put it together with SDL and create what would effectively be a "poor man's Qt" XD

Give it a look, worth your time.