Start with the Greeks, then read the German rationalists, and then Schopenhauer.
Then, and only then, start following this chart in order. Nietzsche is extremely valuable if you know to read him as the nearly erudite philologist and voracious reader that he was, engaged with an immense spectrum of the Western tradition. If you just jump straight into him all you will get out of it is meme self help bullshit.
After that you can get started with the HxH manga.