I may be the minority here, but I actually am OK with the ending. I mean it IS kind of goofy; B memories is a cult that believes that resurrection is real. While stupid I feel it HAD to be mentioned in a death manga. The concept of death is so abstract in many cultures, it's important to showcase religion and their interpretation of death. With the most extreme religions to take death being cults. They target the lonely, the NEETs, just like B memories and they put of the facade that they are purifying the world. Cults follow a logic that SROT OF makes sense, but they satisfy desperation rather than reality. Cults are selfish and the connection between cults, desperate people, suicide, and death is STRONG.
Grieving families aren't willing to move on because they are told a fantasy that their significant other is alive. While we ALL want desperation, while we ALL want no one die, it IS necessary. The bodies NEED to be soiled. The ending would be TERRIBLE if the bodies in B memories came back to life or if an ACTUAL apocalypse were to come.
Instead, the ending was scuffed but SOMEWHAT within the boundaries of Death sweepers. YES, the earthquake WAS scuffed, but we got to see how people acted during their last moments in life. The people who WANTED to end it always find a reason to live when others die, the selfless individuals that want to suicide become egotistical and they celebrate. That "revolution" is what every degenerate who survives suicide experiences.
I HATE the incest and Miwa-san raiding B memories since it came out of nowhere. The old girlfriend's return was also unnecessary and the "stars are shining bright" part is not significant. I don't understand the symbolism behind the stars, it feels pointless.
Maybe I am being selfish here, but I think this manga is peak, 8/10. The philosophies this manga shares makes you think at times and the story is quite enjoyable as well (There are poorly written moments, but the main concepts are still there).