Dell Dongle Extension Not Being Recognized

@Gtrtim112  Long USB-C cables are only designed to carry USB 2.0 data and power.  They are primarily meant to be used only for charging devices.  They do not support carrying USB 3.x data and video output.  Those signals require more bandwidth that cannot reliably be carried along longer distances via current passive cable technology -- which is why the cable attached to the dock is so short in the first place.

I'm not sure why the dock's built-in cable is forcing you to place your laptop on the floor, or why the next most convenient location seems to be on the other side of a room, but that isn't going to be a practical setup.  Depending on the particular dock you have, the longest available cable that will carry the signal it requires will be between 0.8 meters and 2 meters, i.e. 2.5 to 6.6 feet.  But even that doesn't necessarily mean that you can simply swap the cable built into the dock for a third-party option.  And extension cables tend to reduce maximum cable length anyway because the transition between a port and a connector, in this case between the original cable and the extension, is actually a significant source of signal strength loss, which means that when you use extension cables, you might not be able to achieve the desired performance even if each component is rated to deliver it, and sometimes even if a single cable of that same total length would have worked.  To my knowledge, there are no USB-C extension cables that will carry video, USB 3.1 Gen 1 or 2, and 60-100W of power as Dell docks are designed to provide.