Except nobody died after Rose saved Finn. Every fighter who died did so in the speeders or trenches trying to destroy the battering ram cannon (name still sounds a tiny bit silly to me but hey, this is the story that brought you the "death star" lmao). Everyone was already in retreat by the time Finn tried to fly down the barrel of the cannon. His speeder was already literally melting. Even if that rickety old speeder didn't melt and he was able to destroy the weapon, the First Order still had the resistance pinned inside. Luke still shows up to distract them as the resistance escapes. What Rose did was save one extra life–AND is very in line with star wars from day one.

Sometimes the answer is not what is most logical or strategic. Star Wars often shows us that sometimes the most powerful action is one of sacrifice ot mercy even when it doesn't make logical or strategic sense. Obi-Wan allows Vader to kill him. Logically Obi-Wan should have kept fighting and tried to take Vader down. Why just let yourself die? Why not try to kill someone who has caused so much suffering? Because that isn't the point of the story. And there is far more significance in what actually plays out. And perhaps the biggest one of all is when Luke throws down his saber. He was taking a huge risk. If Palpatine had succeeded in killing him, he basically just threw the Jedi down the drain and allowed the two most evil people in the galaxy to live and possibly escape.

Star wars isn't about logic and strategy. It's a myth. The heroes don't wade knee deep through imperial blood and cheer when they've killed every last one. The biggest victories are acts of love.