it was cement truck levels of unnecessary to have the adolescent survivor of the partisan group be so damaged by her experiences that after her death in the twenty-first century, her adult children all conclude she was incapable of loving them...

I think that was probably part of the reason it felt to me like a book very much about hopelessness and destruction. Which is fair enough if that's what you want but wasn't what the book was presented as. Obviously it is the case that some survivors become terrible parents and perpetuate their trauma on their children, but not all of them -- like you I have seen both outcomes. Whereas I do feel that Russell purposefully chose the worst outcome for her characters, even the survivors, not because it served the narrative but because it was satisfying to her as an author. As a reader, I felt that she enjoyed the pain a little too much.