What do you mean? Can you provide some links for building OSX apps with ReactNative? Only iOS/Android are listed as targets on the documentation website (under getting started).
But aren't those 3rd party react native for desktop implementations, just like Proton Native? Does Proton Native differ in some meaningful way that OP was referring to?
We're in a thread about a React Native for desktop implementation.. saying "React Native is React Native for Desktop" is confusing; hence my question.