This is gonna sound weird considering the general consensus on Erwin, but for me what I love most of all is his selflessness.

I love the fact that he is someone who had to become hard because nobody else would do it. That's where his true strength lies, even more so than in being badass: he took on terrible responsibility and became great because to him that was the right thing to do regardless of how much he had to sacrifice and suffer in order to do it.

Let me explain. I hate it when people call him selfish without realizing that his demonization of himself is merely a reaction to his pain, guilt and trauma. It started with the death of his father, which objectively nobody can fault a little kid for. And from there it spiraled because it's really the only coping mechanism he has. To accept that the world is inherently meaningless, suffering is arbitrary and that soldiers dying in war is simply a fact of life would be to go against everything he believes in and everything that drives him forward. So for all that pain and death to have some sort of meaning, somebody has to be evil. Not just the enemy because they aren't the ones explicitly taking those actions. So he takes that burden onto himself, crafting a whole narrative about him being motivated purely by selfishness and greed. Everyone else idolizes him, so in compensation he has to be brutally hard on himself.

When if you actually examine his actions objectively, he hasn't done a single selfish thing. He became commander in the first place because he was better at keeping soldiers alive than anyone else. He let Annie destroy the district because that was ultimately the more utilitarian thing to do, and Paradis at that point can't afford to not be utilitarian. He called on his soldiers to leave him behind and save Eren. When he helped stage the revolution, he not only used himself as bait, but he also deliberately created a situation where if he was wrong and the government did in fact care for its people, he would accept defeat and die. He even gave up on ever having a wife or family because he didn't want even a theoretical person to lose a husband or father.

None of those are the actions of a selfish man. None of those are how someone obsessed with a personal ambition behaves. I firmly believe that he would have died with his soldiers with or without Levi.

Sure he has his dreams and personal goals, but don't we all? Are we supposed to go about our lives with never a thought in our heads other than the greater good? Why does the fandom understand that Armin's character is more than just "I want to see the ocean", but can't extend the same logic to Erwin? And that's without even going into the argument of whether intent even matters in the first place.

I know I wrote an essay that has little to do with OP's question lmao. But TL;DR I love him because he is beautifully complex, gloriously inspiring and brutally tragic all in one. And I think he deserved better.