Responses
Maybe you just had higher expectations and saw more potential in a different ending, but there aren't really any loose ends. Or maybe you wish it would have drawn out longer and taken time developing, in which case I remind you this manga was fast-paced and compact with drama from the beginning. A big twist doesn't necessarily mean rushed to finish.
It seems like the mangaka lost motivation for this and just rushed to the ending. I was anticipating Sumi managing to get the company back, but that abruptly ended. Started off good, middle got bland, and ending was horribly rushed