Dont learn for the sake of learning
I firmly disagree here. One should learn for the sake of one's self. Learning as an indulgence for your ego has nothing to do with trying to show off to others. Seeking to "master" any one subject is much more akin to this.
There is something to be said for focusing on singular topics, but knowledge is not the same as a trained skill. Learning one punch really well is not always better or more useful than being familiar with 1,000 types of punches.
OP, there is nothing wrong with having many interests and wanting to pursue all of them. If that is what you want, go for it. I am very much the same way. In our cases, what is needed is a understanding of your own self, and what is it that you are most interested in at the moment. Studying something and then abruptly becoming interested in something else and switching the subject of your attention is no crime. Devote yourself to that passion wholly until it passes, and then let it go and move on to the next.
In this way, you will not become the "master" of any one punch. If you were to compete against someone who had spent their entire lives studying one philosopher, of course your knowledge would not be able to compete. But, competition is not what learning is about. You aren't seeking to be the best of the best. You don't need to be the best at any one punch. Instead, learn as many punches as you want, and synthesize that learning as you wish. The result will be a unique perspective onto you, a fulfillment of your own unique self.
Some of the most respected individuals in history, deemed "masters" now, became so by synthesizing knowledge taken from multiple areas and used to create a brand new category to master, which did not exist prior. I mean, for goodness sake, that's how mixed martial arts came to be! The best way to learn is whatever comes naturally to you.
Instead of seeking to correct yourself, aim to improve your methods. Perhaps you could make a list of several things you are interested in at the moment, and use that to organize yourself. Put down sources, authors, topics, etc for each category you want to look into, prioritize the ones that look best now, add things as they come up, and so on.