If Bruce Wayne hadn’t decided he personally needed to do all the crime control no harm would have come to Harvey dent in the movies.

This is just patently false. In The Dark Knight, Dent had already been targeted by criminals just for the work he’d done on his own, and the incident that led to The Joker identifying Batman was Bruce Wayne hosting a fundraiser for Dent to run for district attorney, which The Joker had intended to kidnap Dent from to start his turning-Harvey-Dent-evil plan. That was an event full of rich people that already included professional security that was thwarted by the criminals, and the only thing that stopped the kidnapping’s success was that it was at Wayne’s penthouse and attended by Wayne, who could quickly disappear into a batmanning room, put on his batman outfit, and intervene. When it was clear that the kidnapping would be unsuccessful, The Joker attempted to turn Dent evil in a rush by throwing Rachel out the window, and only identified Wayne as Batman later by checking who else she was close with. Batmanning significantly delayed the plot of the movie, and the outcome would have been the same without Batman, except for there wouldn’t have been the silver lining that Dent was seen as a martyr for justice because Batman and Gordon covered up that he’d turned evil and gone on a killing spree.