Sexual selection pressure is massive in evolutionary systems. You’re forgetting that fitness is an indirect result of what is ultimately sexual selection pressure. A lot of people think it’s fitness first, sex second, but it’s actually the other way around, sexual selection plays a larger part, and is supposed to imply fitness, but doesn’t always. Without sex there is no reproduction, and therefore no mutations. Anyways, just remember, in evolutionary systems, they are not directly selecting for traits, they are selecting traits through the abstraction of sex and sexual selection. Sex is king here. IDK it’s weird but it is what it is.