Is there any evidence that karma is real and/or isn’t made up concept to cope with naturally unjust world? Or is world not unjust? (Not joking. I don’t mutilate

Is there any evidence that karma is real and/or isn’t made up concept to cope with naturally unjust world? Or is world not unjust? (Not joking. I don’t mutilate animals, neither do things that someone could call really unethical, but ethics itself always felt so synthetic to me. Nature is not ethical, it is very unceremonious for no “good” reason.)