You are the second person to say this, what are you doing that's faster?
I'm talking from start-to-finish creating the UI, wiring into business-logic, handling UI state, making it fully responsive, etc...
I've used WPF, QT, some old java swing stuff, and the Android studio layout editor, and none of them are a fraction as fast and capable as a well setup react web application (which to be fair, took a good chunk of time to setup).