AFAIK, while there is a standard for Ethernet-over-Thunderbolt, typical Thunderbolt docking stations simply expose the underlying Ethernet controller as a PCIe device, typically using a chipset with drivers that are widely available if not preinstalled on all major OSes.

In other words, they not hubs (or switches) in the Ethernet sense, just a different physical connection to an otherwise ordinary PCIe NIC.

I imagine non-Thunderbolt USB docks are similar, presenting as a USB hub with a garden-variety USB Ethernet controller attached to one of its ports.

With that said, I imagine a "smart monitor" with integrated dock would additionally include Ethernet switch-like functionality, to enable sharing of a single physical Ethernet port (or wireless connection) between the connected host and the smart TV subsystem, just as some servers allow sharing of a single Ethernet port between the installed OS and an onboard BMC.