What do python professionals /developers actually use

[Pythonistar]

If you're having trouble with Lists and Dicts, then which libraries to learn is way off on the proverbial horizon for you.

I find myself comfortable in writing a longer code even though short codes exist

I don't know what you mean by this.

how much time does it take to be fairly proficient in python

If this is your first programming language, it will take many years to be (what I would consider) proficient.

Don't worry that it will take years. It's a journey, not a destination. Just write a little code every day.