I don't agree that React is FRP. FRP is a generic solution that builds data-UI synchronization around data, and assumes that incremental UI updates will be written in UI code. React puts data-UI synchronization code inside UI components and provides an Immediate Mode-like API to avoid writing incremental updates in UI code.

In your world, the incremental UI code lives in the react library, and react applications aren’t UI code, they’re just FRP data transformations.

React components are clearly not FRP data transformations, they don't have any notion of data flows, observable/computed values, etc.