No, it turns out Zeke is the one with the emotional baggage.
Fixing people is tricky work, and Zeke is certainly not qualified to fix anyone. He arrogantly assumes that if he can find a turning point for Eren, he can finally convince Eren of his plan for mass Eldian euthanasia. If the Eldians can’t reproduce they will not be a threat to the world, and the world can finally be at peace. Too bad for Zeke that others won’t willingly choose that plan, hence all his scheming.
It’s ironic that Zeke and Eren happen to be family, they couldn’t be more opposite in their ideas for the future of Eldia.
Zeke, holding the trump card of being Eldian royalty, can direct Ymir at will to do whatever he wants. Zeke foolishly chooses the option of going through Eren’s past in a misguided attempt to save Eren. Zeke’s assumption is that Eren is a victim of their father’s brainwashing. After all, the father was the cause of all of Zeke’s suffering. So in his mind, it had to be the same for Eren? Eren was just following the restorationist plan to bring Eldia to the forefront of world power right?
It’s only after sifting through Eren’s memories that Zeke begins to realize that Eren wasn’t actually brainwashed. Eren had willingly chosen violence from the very beginning. Eren had killed the kidnappers who attacked Mikasa and her family. Of course it wasn’t Eren’s doing alone, but it was Eren’s choice. Zeke was shocked by the memory, and of course so was the father who scolded Eren in the memory.
In a world with violent options, Eren chose to perpetuate the violence. In a world where you were surrounded by death, why not kill those who had chosen a wicked path? Eren didn’t think beyond the immediate situation. He never did.
Zeke ends up fixing nobody, but he does get closure.
Ironically towards the end of the sifting through Eren’s memories, it’s Zeke and his father that end up getting closure. The father realizes that he failed Zeke, and is sorry for all the suffering that he caused. It’s by going through Eren’s memories that Zeke realizes the truth about his father, that he couldn’t see through his own eyes. Trapped in a memory from childhood, Zeke finally gets released from his own personal nightmare.
Of course that release ends up only being temporary.
When we return back to Ymir world, for lack of a better term, Eren is the one who ends up calling the shots and gets the future for Eldia that he wants. The choices for Eren are simple, since Eren never considers nuance. Either the world kills all Eldians, or the Eldians kill everyone else. Very simple, it’s just a matter of survival. Of course Eren’s logic is flawed, but no one can stop Eren from willfully choosing violence. And to make matters worse, Eren holds all the cards.
There of course could be other options for peace. But those require simmering tensions between all involved parties. Rather than play the long con, and attempt to persuade others that they are not a threat, Eren takes the shortest route to perceived victory. While the world had scapegoated and hated the Eldians for millenia, it could have been possible to achieve peace through other solutions.
Sadly when the brain is short-circuited by flight or fight thinking, dialogue isn’t an option. Flight is also not an option in the current scenario. Fight, for better or worse, becomes the only option. If violence is the answer to getting peace of mind, then the mind finds a willing perpetrator for violence.