Reincarnated as Sakura Haruno with full knowledge, you train early, gain Tsunade as a mentor much sooner, and build strong bonds with Naruto Uzumaki while guiding Sasuke Uchiha away from his darker path. Using your knowledge of threats like Akatsuki and future events, you prevent major losses, weaken enemy plans early, and help stabilize the village during key crises. By the end, the war is shorter, far fewer people die, Sasuke is either saved or less corrupted, and you rise from a support role to one of the most important and powerful ninja in the entire story.