I have developed full stack next js ( as a frontend ) and separated express server as a backend, I run in problem when I wanted to deploy it. I'm wondering what'll be the best way to do it without losing next js performances as a framework. I have read some articles saying that the application is good to be deployed separated ( let's say frontend on vercel and backend on heroku ). I developed this project for customer who already had really old website and he's paying for C-panel hosting. I'm not sure what to do, Can i maybe deploy somehow the full project on that c-panel or something else.This is really important to me, and i can't find a specific answer. Thank you in advance.

Here is my folder structure: