Bertholdt said he could accept whatever happens. He still died believing the mission failed.
Marley never needed the Founding Titan back. They needed Paradis gone or broken. The Rumbling wiped out most of the world, but the island still had to live with what was left of it. No army outside the Walls. No real allies. Just the people who watched the rest of the world burn because of them.
Bertholdt lost his life. Marley lost the war. Paradis is the one still carrying the result. If Bertholdt’s side really lost, why is the place he came from the only one that doesn’t have to explain the Rumbling to its own people?
They spent years figuring out how to cut Titans and still never treated the bodies like a resource. People were starving inside the Walls. Titan flesh evaporates, but it can be preserved for a short time. They tested that. They just never scaled it.
Same with night operations. Same with anything that could have come from studying the Titans instead of only killing them.
If the research was only about survival, why did they stop at the blades?
When Armin transformed into a Pure Titan to eat Bertholdt, his form still had blond hair, a skinny body, and a face that looked more human than most Pure Titans. Pure Titans usually lose every trace of who they were. His didn’t.
How did Armin’s keep so much of him right before he took the Colossal?
Mikasa holding Eren back every time he tried to break is the reason he stayed soft until the end. She never let him sit with what he was becoming. Every time he pushed, she pulled. So he never had to own the damage until the Rumbling was already moving.
People call it love. It was the only reason he got to keep playing the victim while the body count climbed. If she had stopped shielding him earlier, would he still have needed the world to burn just to feel like he was in control?