Before you use external libraries I highly recommend learning built-in libraries and functionalities. For e.g.: Try building an HTTP server without 'express', using the inbuilt HTTP module. It will give you a rough idea on how everything works.
Since you're new to NodeJS I recommend watching these two:
Some libraries/frameworks that are commonly used by NodeJS devs:
Advanced:
What else would you suggest except node.js and its modules - as you know I'm from front end background?
Like you said, you're super fast in building apis. What else should I dive into?
Thanks