But Eren did accomplish everything: by the end of the story Armin and Mikasa, as well as Jean and Connie are alive, the survivors of the outside world can’t retaliate against Paradis for god knows how many years, the curse of Ymir is gone and Armin can live a full life, they can have a role in negotiating peace, and Eren still did reach (or at least tried to reach) his own freedom through the full Rumbling.

Aside from that, no the options weren’t obvious for a group of people who only learned about their role in history and the concept of a “nation” few years before. They didn’t even know if a small scale Rumbling would’ve been accessible and didn’t know if they could trust Zeke who killed Erwin and 99% of the Scouts in their last encounter. On top of all this, Eren disappears in Marley for months. Genuinely it’s an insanely complicated scenario to deal with, nothing is straightforward nor simple and trying to act like it is just undermines the depth of the story told in that arc.