I agree with all of your points.
Having only done NativeScript professionally, I can definitely say that the developer experience of Flutter is far superior in everything from hot reload to debugging.
Most of the issues we experienced simply never would have occurred using Flutter, given it’s architecture and the tooling around it.
As a mostly JS dev, I find developing in Dart to come pretty easily, especially since I use TypeScript heavily. I have minor nits about Dart not being as sexy as other modern languages in it’s capabilities, but all things mature with time and popularity.