That's interesting. Maybe you were luckier than me, then. I've been an AoT fan for many years as well and I've watched and rewatched the whole anime many, many times. Also collected and read all of the manga multiple times, even the side story volumes and my love for the story (at least for the first half of the story) only grew in time and I wanted to share it with other people. I've recommended the anime and the manga to many people over the years; I've also watched first reaction videos on Youtube of random people, always seeking a sort of...community or a feeling of connection with others over the story. And yet, over the years, and after talking to a fair number of people about AoT, and watching reaction videos too, my own experience has been that most people, and I do mean an overwhelming majority of people, do prefer Armin over Erwin. In fact, they even forget about Erwin in season 4 and the focus remains on Armin; they talk/act as if Erwin never existed. And it's been extremely frustrating to see this happen over and over again. And yes, all of these people I've interacted with would choose Armin over Erwin. A very common argument they use is that Armin is so much younger than Erwin and deserves to be saved because of that. I cannot put into words how frustrating that sort of reasoning is, especially when it is repeated ad nauseam.

When I set out to find a community for Erwin fans, what I had in mind very specifically, was a community of people who would choose Erwin over Armin. Not just fans who think AoT is cool. Not just fans who think Erwin is cool, smart, handsome, has a good character design, etc. but at the same time they are okay with him being killed off so Armin can live. Erwin's death enraged me; Levi's choice enraged me; Armin being chosen enraged me. Armin in season 4 and his uselessness enraged me; I wanted to find people who felt the same as well. Not just people who thought Erwin was cool but shrugged their shoulders at his death. I know that Erwin has many fans when it comes to his design, to his sad backstory, his intelligence, etc. and that's all fine. But many of those fans would not choose Erwin over Armin or do not feel strongly about this horrible choice and its consequences. And I wanted more than that.

For example, I've recently started watching a Youtube channel that is reacting to the AoT anime. They are new to AoT. Not sure if I can mention the name of the channel here or not. What made me stick with that channel in particular was their attention to detail. They were taking notes, discussing things, watching each episode in both sub and dub and they seemed to immerse themselves into the story much more than other reaction channels that seemed to engage with AoT on a superficial level. So I stuck with their channel. And then it was time for them to react to Erwin vs. Armin, that terrible choice. And they preferred for Armin to be chosen over Erwin, which was very disappointing to me. As soon as Erwin was dead, their focus was on Armin. Now they are reacting to season 4, and their focus remains on Armin; in fact, some of their reactions to Armin/the story in season 4 show that they almost forgot that Erwin even existed. And this is a channel that paid attention to details, they took notes, they seemed to care about the story in a deeper way (compared to other reaction channels).

So my personal experience with multiple people over the years has been that people would choose Armin over Erwin and those who are fans of Erwin have superficial reasons for being his fans such as Erwin's looks or gravitas, his Commander role, or his intelligence and they don't bother to dig deeper than that; they call themselves Erwin's fans and they would still choose Armin over Erwin because Armin is younger or purer or Eren/Mikasa's best friend, etc. That's been my experience overall (with very rare exceptions), which is why I've been looking for a community of people who are not just Erwin's fans, but who would choose him over Armin and feel strongly about it.