I don't really understand what users are doing when they say things like this. What kind of features are you trying to implement?
As a React dev since 2015, things were pretty bad initially in this way - but now you can literally build complete applications with React, react-router-dom (clearly the winner in this regard), and your choice of state management (mobx 6 is, to me, the best). Redux is king and MobX is the slightly more adventurous challenger.
I have built an absolute plethora of applications and I do not have any external dependencies beyond those two, TypeScript, D3, and the occasional helper library (date formatting, deep-equals, etc).
Speaking to some other points as well, the React core is not really minimal at all anymore, since the advent of hooks you can actually completely bypass external state management and just use hooks and your own context. I've done this on a couple smaller applications lately and the hooks `useState` and `useEffect` are actually insanely powerful.
Last but not least, React has insanely strong error messages and linting warnings. Things like non-unique key errors, debug symbols knowing the actual source of errors, stack traces enumerating thru the actual React tree so you can see your error, dependency array validation for useEffect, and more that I can't recall at the moment - it's the top library for UI for a lot of reasons and I think your opinion sounds a few years old.