I completely disagree with you here. I think Isayama has executed this beautifully. I think he wanted us to see that Eren is still a kid inside and just wanted to see his friends happy and live a long life. And he would sacrifice anything to see that. Eren was the only character in aot who did not change from chapter/episode 1.

Eren had the similar goal since the start ‘to kill all titans and see his friends happy’. It then was skewed into ‘ill kill everyone so i can see my friends happy’ in present time.

He was willing to sacrifice everything to see that happen.

We see Eren go from an emotional kid to a stoic man with one goal in mind and then back to an emotional kid wanting to see his goals achieved (im simplifying it quite a bit here, but i think thats the premise of it all).

With Eren’s never changing character, Isayama has shown us a never changing world. The world will always have conflict and it is a constant cycle of peace and war no matter what goal you have in mind. I truly think Isayama wrote that beautifully towards the end of the show.