Who says it's deprecated? If it's the same people who think my Ethernet port should be called "enp0s31f6" instead of "eth0", then I'm afraid I do not respect their authority...
The people who maintained it, the kernel developers, the Debian distribution team? You don't accept their authority? I mean, I know this is a MacOS thread, but that's wild.
Fascinatingly enough, this is Conway's law in action. The Linux kernel doesn't break user space, and ifconfig is on the user space side of that boundary. On BSD, they're organized differently, and went a different way.
https://manpages.ubuntu.com/manpages/stonking/man8/ip.8.html
No, it seems that iproute2 is Linux-first, or Linux-only: https://en.wikipedia.org/wiki/Iproute2
Sad!