You actually can connect two machines via USB-C (USB4 / Thunderbolt) and you get a network connection.
You only get Link-Local addresses by default, which I recall as somewhat annoying if you want to use SSH or whatever, but if you have something that does network discovery it should probably work pretty seamlessly.
The same thing happens with two machines connected via an Ethernet cable, which appears to be what this USB4 network feature does - an Ethernet NIC to software, but with different lower layer protocols.
AIUI, most NICs these days do what is called "auto-crossover"; i.e., they'll detect the situation and just do the "crossover" in the NIC itself. A normal cable works.
You only get Link-Local addresses by default, which I recall as somewhat annoying if you want to use SSH or whatever, but if you have something that does network discovery it should probably work pretty seamlessly.
See https://christian.kellner.me/2018/05/24/thunderbolt-networki... or https://superuser.com/a/1784608