You’re describing differentiation that doesn’t actually exist.
“Decoupling visual design from code logic is one of the pillars of good development.” Totally agree, but that coupling occurs in equal proportions in both Angular and React. ngIf vs a ternary in React is no less coupled. In either technology I recommend putting as much business logic as you can outside of framework specific code.
And regarding putting everything in one file, that’s the recommended path for both Angular 2 and React. Both support placing markup in a separate spot if you must, though their docs (I’d argue wisely) do not lead people in that direction.