The manifest.json for web apps can make your mobile experience a bit sweeter. Force rotation? Check! Home screen icon? Check! Splash loading screen and no url bar? Check, check! Amount of work? 5 minutes!
If you already have a React web app, and consider porting it to a proper phone app, you should consider using React Native. However, you could also use PhoneGap/Cordova, which is done in a heartbeat: How?