I would still recommend Attack on Titan tbh.
in 139 chapters, people hated the last 9 and most people only hated like the last 2 chapters.
The author did a good job of explaining almost every single mystery in the story, so if you like mystery boxes Attack on Titan is one of the best.
People were actually mad with character actions / motivations in the final chapters, but not the world of the story you know? That was the problem with Lost.
I'm also a fan that followed Attack on Titan since 2011, and even though i hate the ending, i still think the world / mysteries were pretty great.
Also, early Attack on Titan, the first season of the anime or the first ~40 chapters or something, are pretty amazing.