So what are the chances the deceased Ushio in the funeral was a shadow? Maybe it's too much copium, but it'd certainly be a way to "save" the real Ushio, if she was never dead in the first place... I don't feel like giving up hope yet that she can still be "saved".
It's kind of depressing to have the main love interest of the protagonist in a time loop manga be... irreversibly dead from the start.