I spent a long time trying to figure out how to base ethics…

I spent a long time trying to figure out how to base ethics and morality anywhere else but in metaphysics. So far without success. I can see how someone would call the things you can arrive at without metaphysics ethics/morality, but I don't think it holds water. From a purely materialist/evolutiobary perspective you can arrive at herd-morality, "the greater good", utilitarianism etc. but these are all pseudo morality/ethics in my mind. Evolution favors those groups that have certain rules among them, but as soon as you get to the out-group, the "other", none of this applies. The out-group is fair game. To establish ethics/morality that aren't situational, relative and arbitrary, you NEED to make the claim of self-ownership, which is by necessity a metaphysical claim. I'm always hoping to hear good arguments that counter this conclusion, but usually they aren't thought through. Millenia of philosophers have tried.