At my old university ~15 years ago, all IPs of all computers were public IPV4 addresses. Any computer plugged in to any ethernet port on campus was given such a "quasi-static" IP address.

Well that's fine; my school did the same thing and other than feeling wasteful there was no-

All normal ports were open - ssh, http(s), you name it. It was the OG zero trust architecture.

Oh. Yeah, open ports by default is... and interesting life choice.