Isn’t this the reverse? Providing USB-C rather from a power source rather than powering from a USB-C supply.
You'd take this thing or something like it, set the DIP switches/solder bridges/jumpers appropriately, get a few 2.1x5.5 (or appropriate) barrel jack to screw terminal adapters, wrap it and a couple wires in heat shrink and hot glue it to the back of your HDD/RPi/etc, and have a USB-C plug to power your HDD adapter.