Zen is not at the center of philosophy, its more the center of psychology.
Id call it a philosophy of mind, which sees mind as the center of everything. So its sort of at the center of philosophy, but also is sort of a form of psychology, since psychology is essentially just one philosophy of mind and different views on psychology are just different philosophies of mind.
Jungs idea of individuation is quite similar from zen idea of enlightment. This whole learning to use all 4 functions in typology is part of individuation process. Just as englightment in zen aims to gain control over ones whole mind, jungs individuation aims to incorporate the unconscious mind with consciousness, essentially both are about the same thing, becoming aware of all aspects of self, so that you can control yourself. Naturally you dont have control over your unconscious, thats why you need to become aware of the unconscious aspects of self and once you are aware of them, they are in your consciousness.
This is bit off topic, but MBTI kinda disregards some of these important aspects of typology. Or doesent really disregard the whole growing as a person, but has bit distorted view on it. The problem is that MBTI sees these undeveloped functions simply something that you dont use or use very little and are stupid. While jungs view on it is that we use the functions, but we use them unconsciously and thus have no or very little control over them and instead they control your consciousness and conscious(developed) functions. Without realizing this important fact, you cant really start to develop them properly. Not saying that its impossible with MBTI, just that with MBTI you learn them more by simulating and copying them and you dont really learn the fundamentals by copying something.
Its like you learn to use the function(or behave in the way the lower functions would make you behave), but you dont really learn to get control over the function and it still has some unconscious control over you, you dont become enlightened about those aspects of self