He was a psychologist, but his books are much less about psychology and more about philosophy of society, the mind, and the nature of evil. There are elements of psychology to it, but it has more in common (from a literature perspective) with Marcus Aurelius than a Jung.

Yeah he was at the forefront of popular philosophy going from edgelord existentialist nerds to edgelord hacks completely devoid of meaningful philosophical consistency. Ironically, JBP is the embodiment of postmodernism