Game-dev -- way of expanding myself

First of all - hi.

I'm a high-school student fond of developing. I have about 2 years of experience with Java. Recently I started transitioning to C#. So here comes my question: in my current state of knowledge and with a desire to expand my skills, what is the best way to get into game-development and in future - to get into some game-dev studio?

I asked this question once somewhere else, I got some really confusing answers. I must say - I'm not interested in Java (so such libraries like LWJGL or libgdx fell off), I have made a chess game already in pure Java. It would be better for me to learn C# or C++? And, what's more, should I learn to use libraries like SFML and "re-invent the wheel once again" (as I was told to) or jump straight to some engines/libraries like Unity, Unreal Engine or MonoGame (I'm aware that MonoGame is different from UE or Unity)? Or maybe there's a better way to be actually good at making games (apart from actually making games of course)?