Extending docking station USB-C?

I am looking to have my laptop's docking station placed on a credenza under a large screen TV and my laptop on a conference table....

Thought I could just get a USB-C extension cable .....but using it, I do not get display on either the TV or my computer monitor (when connected to that instead).

The extension cable has a power port for a 12 volt adapter, and I added that, but still no good.

Any ideas?

I am going to net try to get a male usb-c-->male usb-c cable and turn the extension cable the other direction to see if that helps.