The "new personality" is the inauthentic cult personality that they want you to put on to be under their power.
I'm a far better person out of the Borg than I was in. I'm accepting, far less judgmental, loving, happy, helpful, etc. I have genuine interest in others, not just so that I can preach to them. I try to understand others instead of thinking that they need to understand what I understand from the cult that indoctrinated me. Life is amazing now. The results of the "new personality" were ugly, caused dissonance, and subsequent mental issues that all dissipated once I woke up and found freedom. The "new personality" is a prison of one's own making at the behest of the governing body of overlords.