The thing is, AOT isn't One Piece, or Naruto, or Bleach etc. where the journey is greater than the end goal. AOT the end goal is by far a bigger deal than the journey, almost nothing else matters. All plot points, all the hype scenes, characters etc. everything is for the end result. Once the ending is dogshit and you know those "mysteries" amount to nothing, there's not much to go back to and enjoy. AOT went from being the best anime had to offer, to not even worth a single rewatch.
If the One Piece is something stupid, I can still go back and rewatch cool One Piece scenes, because the journey is what made us fans of this series.
I think to each his own but I can still rewatch / read AOT no problem
The first battle where everyone died is still insane
the fear of the titans etc still real
the boulder thing
Later too the Annie fight, the first Reiner rebel and fight, the Zeke intro and the whole being broken, Erwin, Jean etc, etc etc etc
AOT has so many great moments I can watch again no problem
and more importantly the feelings, emotions and excitement I had watching / reading it will never go away even if the end was bad as fuck
And it’s more important than being disappointed
I prefer reading a manga that have 10/10 parts but also 2/10 than a manga that is always 6-7/10
Way more worth it and fulfilling