I assume that those USB-C connectors were USB 4 or Thunderbolt, not USB 3.
With Thunderbolt and operating systems that support Ethernet over Thunderbolt, a virtual network adapter is automatically configured for any Thunderbolt connector, so connecting a USB C cable between 2 such computers should just work, as if they had Ethernet 10 Gb/s connectors.
With USB 3 USB C connectors, you must use USB network adapters (up to 2.5 Gb/s Ethernet).
With Thunderbolt and operating systems that support Ethernet over Thunderbolt, a virtual network adapter is automatically configured for any Thunderbolt connector, so connecting a USB C cable between 2 such computers should just work, as if they had Ethernet 10 Gb/s connectors.
With USB 3 USB C connectors, you must use USB network adapters (up to 2.5 Gb/s Ethernet).