He Traveled Through Time and Became the Protagonist but Couldn't Handle the Supporting Role?

Hello everyone, my name is Nie Dulin. Due to some strange combination of circumstances, I inexplicably traveled through time in a novel, and became a protagonist. However, I can't get the male supporting role for my protagonist! I originally thought that as the male protagonist, I could kill everyone and have a harem of three thousand beauties! But the ending of the original work sucked. . . Intention: Hehe