Is this necessarily the case? How can a species evolve without natural selection (the engine of evolution)? If you don't have natural selection acting as a 'fit

Is this necessarily the case? How can a species evolve without natural selection (the engine of evolution)? If you don't have natural selection acting as a 'fitness filter', how could a species change in any coherent way? It seems like genetic diversity would increase, but it's not clear to me that, when ~95.4% of a species survives to adulthood, there is any pressure that could push the whole species (or even a subset of it) in a given direction.[0] [0]https://ourworldindata.org/child-mortality https://ourworldindata.org/child-mortality