Couldn't have said it better myself, the rumbling arc is underwhelming but the last chapter is just next level badYes, the last arc was very underwhelming and the ending was ridiculously dumb.
Making Eren a puppet for Ymir all along who was just moving on the destined path and killed his mother from the beginning to kickstart the journey ruined his character completely beyond repair, threw all his development out of the window and made ton of scenes from old seasons look laughable now after they were emotional previously. Ymir's target being out of her love for the king and she wanted to learn to move on was dumb. Eren's plan of killing 80% of humanity then get killed to paint alliances as heroes was dumb as feck and ended up solving nothing and serving no purpose because the world still hates Paradis and the war will still go on so what's the point exactly? The alliances now being the peace negotiators from the world towards Paradis is dumb, and lolz at the end that seems to hint at Eren becoming a bird or something, how can a random bird be so intelligent to wrap the scarf around Mikasa's neck then fly again? So dumb. Actually how did Mikasa travel from Marley to Paradis on her own holding the head? Did she ride a plane or a boat with the head alongside her? Dumb.
Honestly the entire rumbling shit arc was very underwhelming. The series was great up till this arc, after that it was just clichéd save the world bullshit, turning the conflict into a simple everyone against Eren, turning Eren into an off screen main villain just to pull out a Code Geass rip off ending and throw all the build up you did for the character in the previous 3 arcs is underwhelming conclusion to such long journey. To make him be the one who killed his mother was the final straw. Eren went on from being a potentially great protagonist to a terrible, underwhelming one in space of one arc
That particular page where Armin thanks Eren for becoming mass murderer makes me want to vomit . Honestly Mikasa, Armin, and Eren must be one of the worst MC trio of all time, every single characters other than them are way more interesting and more likeable