Hello. I didn't fully understand what kind of dilemma you are facing?
In many ways, the choice depends on whether you have strict time limits and what quality the final app requires. If you need to build an MVP application with which you can test a hypothesis and you have little time to develop it, I would recommend Framework 7. The application will be quite working and it will be enough to test the hypothesis. And the development speed will be higher, given that you have not yet worked with Flutter / Dart.
If you need to develop a productive application, not just for a hypothesis, but for full-fledged work, and the development schedule at the same time allows you to learn new technologies, then it makes sense to implement the application using Flutter. Today, in the world of cross-platform application development, Flutter has secured the title of best practice. He has a large community that is actively developing. The framework itself is actively developing. There is a lot of documentation.
As for your expression "a lot of code". Flutter is a framework for programmers, just like Framework 7. If you started developing an application on F7 without using a Wappler, you would also face the problem of "a lot of code". Moreover, the Wappler supports F7 in two versions:
- As a custom build, with full integration with App Connect.
- In the basic version, with partial integration with App Connect.
The difference is that in the first option it will be very easy for you to work in the Wappler, but part of the functionality of F7 will not be available to you. And in the second option, you will completely get all the features of F7, but from time to time there will be situations when you have to write code.
I also want to note that Flutter is not only actively developing on its own, but the infrastructure around it is also very actively developing. Low-code development tools for Flutter have already appeared, such as https://flutterflow.io and https://teta.so They are still very raw (teta.so haven't left the alpha version yet) and they don't have many functions, but they are very actively developing. There are quite a few Flutter developers in my environment who are already using FlutterFlow to speed up interface development. They quickly develop the interface using FlutterFlow, download the code and pass it on to development to add complex logic. Even this approach speeds up development. At the same time, this is data from both freelancers and developers working in large studios.
In conclusion. My opinion is that the future of mobile development in the next 5-6 years is definitely for Flutter. This is the standard of a high-quality cross-platform application. Will Flutter appear in the Wappler? I don't know. Our community is very different, but we can confidently say that there are quite a lot of conservative people in it. For this reason, many innovative proposals are simply ignored by the community (why invent anything else when there is PHP? 
).
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