When you have low self-esteem, you have lost the ability to set your limits. Maybe you can't even feel that you have any limits. Perhaps you can feel them, but cannot express them or retain them.
Setting boundaries is something you learn very early in life, and if your boundaries as a child have been overheard, reprimanded, rejected or misunderstood, then you learn that you are unimportant, unimportant and/or unwanted. One therefore learns to override one's boundaries in order to avoid these unpleasant feelings.
The treatment of low self-esteem is primarily about discovering how one's own natural boundary setting has been interrupted and discovering what strategy one has made for oneself to avoid feeling the feeling of being unimportant, unimportant or unwanted. Furthermore, it is about feeling and training a new set of limits, and through that finding self-love.
In my treatment, I work with a combination of conversation therapy, exercises and awareness training, just as I encourage you to train (concrete things you discover with me) outside the therapy room.
It is very different how long you have to go to therapy to treat low self-esteem. Sometimes it goes quite quickly, other times it requires treatment over a longer period.
It is very individual and depends on many factors; how motivated you are and how willing you are to change, and not least it is of great importance how early the mislearning/habit arose, as well as how many areas in your psyche it has propagated to, but I have never had any clients, because who has not succeeded.