I worked with React.js for more than 5 years in a big projects and I finally burnout of it, I agree with all you said, React added a extremely complexity for simple thing, added a lot of side affects that sometimes are hard to debug and fix, fix re-render will be your daily work more that create features and in the end you get a slow application in mobile devices due the size/re-render etc.
In the end I decided to re-evaluate was I was doing, I want make the web better but with React.js I was doing worst the web
I think is because JS is one of the few languages that has practically always been used with a layer on top, before with Jquery or other libraries and now with frameworks, that is not so common in other languages, JS has an external layer for everything
In the end I decided to re-evaluate was I was doing, I want make the web better but with React.js I was doing worst the web