Hi Vipin, to quote:

When it comes to performance, Flutter has the upper hand as it’s compiled to ARM or x86 native libraries, which makes it really fast. React Native isn’t compiled to native code, and it still has the JavaScript layer, making it less performant than Flutter.

React Native uses a JavaScript bridge runtime.

Some links for your information:

https://www.thedroidsonroids.com/blog/flutter-vs-react-native-what-to-choose-in-2021#:~:text=When%20it%20comes%20to%20performance,it%20less%20performant%20than%20Flutter.

https://reactnative.dev/docs/javascript-environment