You might have misread the thing I was proposing. If your application "keeps getting more and more complex due to the functionality requirements" then by defini

You might have misread the thing I was proposing. If your application "keeps getting more and more complex due to the functionality requirements" then by definition there's no off-the-shelf library or service that can help. If your complexities are known in advance, you can choose a pattern which builds good, simple, composable code. Honestly even if you're complexities aren't known in advance, it's still easier to build composable solutions out of off-the-shelf parts.