Natural selection is not an entity in itself. Rather it is the name we give to the tendency of those organisms equipped with (heritable) traits that better equip them to successfully produce offspring (which will themselves grow to be viable adults) to be more successful in doing so -and therefore to pass on those traits.
(Please read that carefully - the bracketed bits are essential to a proper understanding, but omitting them produces a simplified version which is close enough to get the idea)
Thus, natural selection would be better compared to "death" than an "angel of death". And really I can't see how this definition could be considered "metaphysical".
I also have to question what you are putting forward here. Are you suggesting that we should place science with a false "mythology" that - you believe - would encourage people to act differently ? I have to say that I do not think that that would be a good or practical idea.