Being on the loosing side with a couple of loved languages, I learned something that I always promote in any project I am part of.

Only use platform languages for production code, anything else just adds more FFI, debugging effort, lack of tooling and impedance mismatchs.

So for portable mobile apps, I am a big supportive of C++ with native views, or just plain mobile Web, specially now with PWAs.

For customers only focused in a specific platform, then full native.