A cloned app is not a great option if you’re starting a new business. Yes, building an app like Signal would be a lucrative option but clone apps are not flexible. Custom solutions are tailored to your needs. They are built from scratch and will have all the features that you require. You can even update and integrate more features over time.
A cloned app is a fixed solution, one that you can’t update. A custom, on the other hand, grows with you. So, I would recommend opting for a custom solution.