>Thinking Eren did it for his country
That is your first mistake. Eren only gives a shit about himself and supposedly his two childhood friends. If Eren really cared about his country he wouldn’t have advocated for his childhood friend over a military commander to be kept alive. He also wouldn’t have basically burned every bridge that his country could’ve made because of petty reasons like being family-zoned or the world not looking like his friends storybook.
"Supposedly" his friends? If he didn't even care about them, let alone Paradis, then what the hell were his motives? It would all make even less sense then. Was it all to get that stupid smile on Ymir's retarded face so she can fade away satisfied, and
nothing else? I can't imagine that's true, it would sincerely be the dumbest thing ever.
And I don't know what you mean about Eren being "family-zoned". I can only assume you're referring to when Mikasa answered to him that they're family, but even the most oblivious retard knows that's not her real answer. All of her
excessive doting obsession over Eren aside (well beyond a
familial normalcy), her expression when she gave the answer showed that she responded out of embarrassment at the sudden question.
Everyone in-universe, including Eren, knows that Mikasa wanted his dick. When Armin was talking to Eren in the final chapter he scolded him for disregarding Mikasa's love. Eren was pretending to be aloof, got socked for it, then received an earful, but just kept up that same aloof expression through Armin's lecture. Then when Armin concluded "well maybe she'll get over you and find someone else", then his act fell apart and we get his blubbering admission of his true feelings.
And it isn't like the series is subtle with Mikasa's feelings. She literally can't keep her eyes off of him, the very first thing you ever see in the anime is Mikasa stealing glances at Eren in the opening theme. Then at the end, there's that gross decapitated kiss they share, and then even when she fucking
dies she's buried with his scarf.
But I'll grant you that the world not being exactly like his friend's book factoring into things at all is, at best, insane. The only explanation I can muster for that is his mind was warped by his power, which he also sort of alludes to in that last chapter. Even that's better than doing things to satisfy Ymir though, I really hope they change a lot of this stuff in the anime, but I don't think they will.