Killer Ethernet is just a fancy name for QoS settings, despite the myth around this, you don't get "faster internet" (like the CPU Turbo button that didn't increased speed but actually set it to its default frequency) you simply get the regular speed by limiting how much bandwidth is assigned to X port of your router, a software that can emulate this in routers that don't have QoS settings is NetLimiter, but it'll only affect your own computer and not others.