Natural selection is the Achilles heel of Darwinism. Darwin saw Malthus’ population theory as the basis NS. This has never been established scientifically and I would submit is dead WRONG. Nonetheless Dawkins still supports Malthusism and many scientists are trying to demonstrate how conflict might lead to cooperation.
There is a long history of dualistic thinking where change is generated by conflict, Being vs Non-Being, (which does not rally work either,) so maybe we should not be too hard on Darwinism. However Darwinism is supposed to be science, which means that it is supposed to be based on scientific evidence, that is experimentation and/or observation. Darwinian NS has none of this.
The result of the failure of Darwinian NS as a system leads multiple concepts of how it works, so evolution as it now stands is not a Theory, but a family of concepts, none of which are acceptable. My own theory for why evolution is so messy is based on a nondualistic, nonlinear understanding of Reality which goes against monististic, linear scientism. See my book, DARWIN’S MYTH.