I'm just wondering who has taken Kant's ideas and still explicates on duties to oneself including the duty of being true to who you are, to be authentic. I know existentialism also considers the notion of choosing to be yourself. Is this still an active topic of philosophical discourse, and if so, which philosophers, schools, and theories are active in discussing this?
I think Kant's notion of duty isn't so much as a responsibility or necessary completion of any task that one is tasked to do. Rather, he is referring to "duty" as a moral imperative in the sense that, we all ought to do things, especially moral things, that can be willied as universal laws i.e. these things can also be done by others. So, if being true to who you are can be willied into a universal law, then I suppose Kant would say that we have a duty to being true to who we are. But, once again, I think Kant would not directly label any acts as "to-do" or "not-to-do" in that connotation of a duty, rather, his answer would rely on the entailment relationship he created to sieve out what we ought to do and/or ought not to, so if anything passes his entailment "test", then we ough to do it and vice versa.