I personally prefer using many smaller components over using a large opinionated framework. But I'm not a big fan of React, so this could be better and worth a try.
It's less a "large opinionated framework" and more "fewer components overall. There is no HTML/CSS for example, it goes direct from Dart (equivalent to JS) to the Widget rendering system."
Dart has its own build tools and package system that work well. You can still pull in dart libraries as you need them. Dart is also a much better language than JS. I can't tell you how many days I've lost to react/JS build tooling issues. A single problem can easily eat an entire day. With flutter/dart I haven't had a single issue like that.
