You’ve taken us round the back way to Nietzsche’s ethics! But on the way I fear you have given short shrift to other options I think are quite viable. Buddhism, for example cultivates the exact sort of universal empathy you say would be impossibly contradictory. Well, the Dalai Lama simply says “practice kindness.” I don’t this there is a compelling argument against that… And Taoism simply advises one follow the way of the Tao. To strive to live in harmony with nature. That might be hard in our modern world, but it’s a pretty good guideline much of the time.