I think you misunderstand what I mean by true self. Yes, our self does change at every moment and is "reborn." However, it is still a true self as it is not artificially modified.
There is no basis for me claiming that artificially modifying one's self is a bad thing, as I never made that claim. I only pointed out an observation.
I find it extremely doubtful that you can actually give a definition of "true self" which meets the following conditions: 1) coherent and non-contradictory, 2) in accordance with reality, and 3) something a person should care about preserving.
I find it even more doubtful that you can give a definition of "artificially modified" which is meaningfully distinct from natural change.