Greetings, tanbay
Good metaphor between low self-esteem and the iceberg. I am a psychologist and I know this iceberg theory, in which the vast majority of our "mind" is hidden. I am not a psychoanalyst, my line is cognitive behavioral therapy. In fact, the precursor of her, Aaron Beck, lives there in the USA. Self-esteem is well-formed during childhood and adolescence, usually from family rearing, from the environment the person lives in, and from their interpretation of the world. This generates beliefs in it that become fixed over time. If these beliefs are bad, they will tend to make that whenever she comes across something, thoughts arise in her mind that she is not capable, for example .... This undermines her ability to solve problems and deteriorate her self -for example. It's something too big to unravel in just one text.
Thank you and good evening!
Wow I had no idea you are a psychologist :O That's awesome!