Okay, new theory.Like honestly, what is their plan? Eren has Godlike powers and could just instantly kill anyone who came at him. Of course, Isayama won't do that. But he's never been consistent.
Levi kills Zeke by eating him and then turns into a titan-shifter. He then climbs Eren in his monkey-titan form like he's fucking King Kong, and brings Mikasa along because the power of love, and friendship means something now. Mikasa cries out to Eren to stop, and that she does love him in a romantic way this time, and Eren stops his racist global genocide, because his Love Quest is now complete.
He, and the Marleyans are completely forgiven, because consequences don't exist in this world. Oh, and I guess Historia has her baby, and the father is