Your definition of “improved” isn’t in line with what nature is valuing, fair enough.
What if nature is making the best choices, the best mate selections and advancing the most superior beings, and you are simply unappreciative of what these things actually constitute?
Shoulds and oughts are after all only worth mentioning if they counter what would otherwise be done. There is no point moralising about how one should adhere to gravity, because that is going to happen anyway, and there is likewise no point moralising about how one should defy gravity because that is not possible. Morals are made in line with that which is possible, but they are suggested to skew that which would otherwise happen anyway. Your moral expectations of what are the best choices, mate selections are are going to be possible, but they are going to be skewed versions of what is otherwise going to happen whether you like it or not. The skewing may have some effect, but the default is amoral. If all your appreciation is for the moral, and the moral is only a twist on the default, then you are lacking appreciation for the default valuation on what are the best choices and mate selections.
It takes some humility, but it’s possible to see all these seemingly immoral choices in what nature selects for the truly moral. Sexual selection is going one way or another, whether or not you think it’s going in the “right” direction. Maybe its direction is better after all, and you/we don’t see how yet?