My view may be simplistic, but it is this: novels engage the reader by telling stories. An ambiguous end to a novel is not a problem -- ambiguity is fine. In fact, it may be the most truthful way for a novel to end.
We should all periodically revisit the best books and films on the Holocaust, however unpleasant, to keep our own awareness, watchfulness, and revulsion very much alive. There is no shortage of worthy choices.