To explain again: docker run --net=host should work. It does work. It attaches to the ports on the host machine which is the virtual machine inside xhyve.
If you expect it to connect to your Mac’s host ports, then no. It will not do that, because it’s running on a virtual machine.
“… it’s similar to Docker Toolbox with a VirtualBox image running docker natively.” which didn’t support --net=host except insofar as using the host ports on the vbox machine, and not the OSX machine.
Why would one ever think changing virtualization engines would change that?