I know almost no JavaScript. I know C and asm and python. So... looking at the two, guess which one looked better to me?
The code for Dart just makes sense. It’s not beholden to JS or XML or HTML or CSS. It just does it’s own thing.
If you are heavily invested in JS, I bet there are aspects of Flutter that are still appealing, but if your aren’t invested in JS, I see no reason to get in just for React sake.