My first attempt in deploying Node.js to cpanel has not really been funny. It turned out that app.js with cjs syntax works fine but one with es6 module ("type": "module" at the package.json) returns "503 Service Unavailable. The server is temporarily busy, try again later!".
This took me couple of hours to figure out what i was doing wrong...
I will appreciate a possible solution to make a node.js with es6 module work in cpanel.