The answer to this usually comes down to experience, time and cost. An excellent developer can build a native app that will work flawlessly on whatever platform it is designed for. But it will most likely take a while to make and the cost will be higher than building in Flutter. The only drawback to Flutter is that it does create some artificial boundaries to how your app looks. If you need an app that is very unconventional looking, you may be better served with a native app.