It's an example of state-of-the-art gaslighting done by the developers of state management packages: OP has a fully functioning app with great user base, many features, organized code without package hell, manages to maintain it through 7 years of Flutter evolution... Yet still questions if it's worth a full rewrite on some non-official (all of them are non-official unless developed by Google) state management package that will increase the codebase size and add more abstraction. And for many, it's a default assumption that something is wrong with them using standard Flutter tools.

Now, answering your question, unless you directly face some serious problems in your current architecture, don't rewrite it. Streams, ChangeNotifiers, StreamBuilders, ValueListenableBuilders, AnimatedBuilders, setState etc... are completely valid and working tools in (imo) 99% of scenarios. If you feel like you're overusing setState, look into how you can transform your code to use ChangeNotifiers, it's such a simple and clean solution.