If you're using a USB-C port to connect a computer to a display, you're most likely using DisplayPort Alternate Mode (Alt Mode), and due to non-existent adoption, we can pretty much guarantee you're not using HDMI Alt Mode. According to the HDMI Licensing Administrator (HDMI LA), you never will because the feature is dead.
HDMI Alt Mode allows HDMI video signals to travel from a USB-C port to an HDMI host, like a TV. It's similar to DisplayPort Alt Mode, which lets you connect DisplayPort displays to USB-C ports. NotebookCheck spoke with HDMI LA, which is responsible for licensing the HDMI Forum's HDMI specs, at CES 2023 in Las Vegas last week and learned that there won't be any certified adapters supporting HDMI Alt Mode over USB.
"According to HDMI LA, there are simply no more uses for Alt Mode," the publication reported on Wednesday. "One of the reasons is that companies like Apple have begun putting HDMI ports on their products again. HDMI Alt Mode also no longer offers any advantages. As a result, the specification will not receive any further updates."