Another thing that doesn't get mentioned is React Native is much easier to staff talent for. Flutter can be better than RN in every single way and companies will still choose RN because it's easier to integrate into the org.
If you have a webapp built in React, it's going to be very easy for you to spin up a React Native app, mostly because you can pull those React devs into RN without much of a fuss. With Flutter/Dart though, you will have to hire outside specifically for the role, even if you hire a "React Native" developer, it will be easy to transition that dev to regular React if org needs change, Flutter/Dart are more brittle in that way.
If you have a webapp built in React, it's going to be very easy for you to spin up a React Native app, mostly because you can pull those React devs into RN without much of a fuss. With Flutter/Dart though, you will have to hire outside specifically for the role, even if you hire a "React Native" developer, it will be easy to transition that dev to regular React if org needs change, Flutter/Dart are more brittle in that way.