Why NextBSD
The machine already knows what hardware it has, how to put a picture on the screen, and how to get on the network. You should not have to tell it.
Kexts carry their own device IDs and the kernel scans the live bus. Plugged in is configured.
Boot it in UTM, QEMU or VirtualBox and the display just works, at a proper resolution.
Boot to a writable root. The image is never copied into RAM, so there is no boot delay and no memory tax, and your disk is never touched.
Services are plists, not shell scripts. launchd is PID 1 — parallel start, launch on demand, and whatever dies comes back.
DHCP fires the moment a link comes up. Bonjour is in the base. Wi-Fi waits for the handshake before it claims to be connected.
libdispatch, libxpc, CoreFoundation, IOKit. The actual Darwin runtime on a BSD kernel.