Another study on the Dark Triad. A measure of authenticity predicted relationship satisfaction for people who scored low in trait psychopathy, but the opposite for people who scored high.

Among those low in psychopathy and sadism, living authentically predicted lower hostility toward others and having less “rocky” relationships. However, among those high in psychopathy or sadism, these ties were weaker or no longer existent.

The findings indicate that “the relationship between authenticity and well-being may depend upon the personality traits being expressed,” Seto said. “In our research, authenticity was associated with positive interpersonal relationship quality when psychopathy was low, but not when psychopathy was high. This means that authentic expressions of psychopathy may impair interpersonal relationship quality.”

https://www.psypost.org/2021/08/psychopathic-tendencies-appear-to-disrupt-the-link-between-authenticity-and-relationship-well-being-61696

These findings are relevant to the dating advice of "be yourself." This is fine advice if your actual self is good. If you're actually high in antisocial personality traits then being yourself isn't great advice. We see this a lot with Nice Guys(TM)/TRP/incls who claim the "blue pill" advice of "just be yourself bro" didn't work for them. This may be one reason why: being authentic doesn't work if your authentic self is antisocial.