Basics of Self-Knowledge

How can we achieve success by knowing the basics of self-knowledge?
Strategies to build successful relationships through self-knowledge, and so on.
You have probably come across these topics before. However, what does self-knowledge really mean?
Advertisements and various psychology and success classes that claim to help us know ourselves refer to which part of our existence? Does knowing my personality type or being aware of my interests and preferences mean that I truly know myself? Or if I know what goal I want to pursue or what beliefs guide my life, does that mean I have achieved an understanding of the basics of self-knowledge? In fact, what we usually hear about self-knowledge is different from truly knowing our true self. Our true self is not something that is one way today and another way tomorrow. It has fixed characteristics that if we are not aware of, we cannot have a proper understanding of ourselves, our needs, and the purpose we are created for.
More importantly, unless we know ourselves and get acquainted with the basics of self-knowledge, we cannot determine our true worth and value. As a result, we may pursue a lifestyle based on an incorrect viewpoint about ourselves, which ultimately does not lead to our happiness and peace. In fact, not knowing our true self is the very factor that causes all our problems, dissatisfactions, and sadness in the world. How can we expect to meet someone’s needs and bring them peace when we neither know them nor are aware of the different dimensions of their existence?