First of all, React Native is not a Language. Secondly, I always suggest learning the native technologies. But if you must learn an Hybrid technology, I will suggest Flutter. I probably have not done enough tests but I find that Flutter Apps are more fluid than React Native Apps
With the latest update of flutter, I also believe that Flutter is the way to go for mobile app development, and thus flutter developers have a good future too.
Since Flutter has already been mentioned a few times here. I'll suggest a few others you should check out if you find that flutter is not for you. 1. React Native 2. Ionic Just like Flutter both of these technologies are great if you're looking to get into cross-platform development. I recently came across this post that did a pretty good job in comparing the two - https://buttercms.com/blog/ionic-vs-react-native
Another vote for flutter. I went to udacity during a sale and bought a number of courses, still deciding which is best. Very easy to learn if you have programming experience. Tightly typed which will no doubt make more sense with more complex apps but I have a number in the pipeline and already feeling confident that I'll be able to knock them out quickly.