That is true, but it is somewhat alleviated by the fact that react restricts what you can (or should) do in a component. A good component has one-way data flow and behaves like a pure function (modulo some AJAX, or interfacing with non-React code, but you can isolate that pretty nicely). Yes, it is not enforces, and JSX can be a footgun. Also, the separation of concerns is along a different line (not markup / behavior / style, but between components. If you want to "theme" your website, its kind of hard). I'm not a diehard functional fan, but I find if you go with it it can actually be pretty maintainable and clean. Tooling is also very good, especially with TypeScript (TSX).

TSX has kinda driven me nuts because react-redux connect doesn't seem to type cleanly. Has that improved?

I haven't tried redux with tyepscript yet. One thing that doesn't seem to be typed correctly is immutability-helpers (it catches some errors, but some stuff seems to be `any`).

It is impressive though how often you have types when I wouldn't expect it.

This is why the React Inspector exists, and it's very very good at what it does.