Flutter Ambient UI - What should be the optimised approach for production level responsive app in web, android and ios platform using single codebase?

Question

I was trying out flutter platform to create a multipage website with android and ios responsiveness using single codebase for my flutter app. I've already tried some single page samples in flutter which are following,

1. Flutter web, android & ios using Stacked architecture & Responsive_builder
2. Flutter web, android & ios using MVVM & Responsive_Framework
3. Flutter web, android & ios using simple Getx package.

All of them are working fine, but what I want is to collect your opinions who have already created a production ready app in flutter web.

Should we consider using Navigator 2.0 for flutter web responsiveness?

Does responsive_framework package work fine if we have complex designs because I'm not confident about the font size and styling application using it?

Can we use any other app architecture, responsive package, design pattern or any other concepts for multipage production level use cases.

Any suggestions would be appreciated.

Thanks.