Best way to replicate or "clone" an existing custom Sales Force app for a new third-party integration?

Hi everyone,

We recently built a custom Sales Force application in a sandbox environment that handles data sharing with a third-party API. The solution involves custom screens, automations, and data sync back and forth with the external system. 

Now, our client wants us to do the exact same thing for another third-party API integration, using the same overall structure and business workflow.

What is the best way to approach this?

1. Should we replicate/clone the existing application inside the same sandbox/org and adapt it for the second API?
2. Or is it better practice to package and deploy the build into a fresh, separate environment for the new integration?

If you have done something similar, what would you recommend, and what are the key things or common challenges we should keep in mind before starting?

Thanks in advance!