Maybe AoT's ending wasn't that bad, at least not as bad as The Boys
why would it be considered bad?
Its exactly what I thought would occur, Eren commits to the only plan that can buy his friends a lifetime of peace, its just that plan is so horrific no one else could conceivably commit to it, and the only reason HE is capable of it, is that his entire life was manipulated by Ymir, and even if he felt otherwise, the timeline is fixed, its deterministic, which he was also horribly made privy to.
The Author, whether he admits it or not, reveals a dark truth with this tale, that for your people to be free of other tribes attempts to annihilate yours, requires immense violence, there's no negotiating with people trying to destroy you, they try after his death for decades, and eventually, decades later, those survivors of Eren's onslaught do indeed destroy the Eldians.