Help using usb c to power display
I doubt that your setup is going to work. I see several issues:

The USB-C-to-HDMI adapter most likely expects a power supply of 5V on VDD. If your YZ12PDN board negotiates 12V, it will likely kill the adapter.
Video data is transferred using USB-C Alternate Mode. In order to activate it, it needs to be negotiated via CC1/CC2. This is in conflict with YZ12PDN use of CC1/CC2.
I'm not aware of any computer or laptop that can provide 12V. The USB-C specification certainly allows it. But I've only seen it implemented in power supplies.
Video data is transferred using high-speed data rate requiring properly shielded cables with controlled impedance. Flying wires between break-out boards will not work. They will pick up noise, distort the signal and make it unusable.