Our current app is so huge, testing takes a lot of time, it has a lot of legacy code and it is too messy. That's the main reason behind building the new feature

Our current app is so huge, testing takes a lot of time, it has a lot of legacy code and it is too messy. That's the main reason behind building the new feature in different project. And we are not rewriting we are adding new features ... So the monolithic part will stay there for ever. Just we want a clean way to do it.