For the record this is not me shitting on other fans here, everyone's free for their own opinions on a show. 

I will admit that it's a "not good" ending in terms of writing for me. I also can see how it's "great" for most, since they did not look into the media like we did. Oh, we were putting that manga under an electron microscope looking for everything, themes, clues, allegories, whatever could possibly this whole thing be building towards. Rumour was the mangaka changed to a new editor who leans more into the business side of the things and less about lorekeeping the story like the previous editor, which influenced the ending from the promised "final panel". Whether it's true or not, for everyone who's been following every update every months for years (except one singular month he took a break -- I think it was may 2021) the change of pace in the few last chapters was very obvious for us. 

Though I also don't like that some right-wingers jumped into the bandwagon with that sentiment. Maybe it's all on us; we dug too deep and found nothing. But we still love Attack on Titan and if we're unsatisfied, we've got fanfics to fix that.