https://www.amazon.com/USB-C-USB-Windows-Transfer-Cable/dp/B...
which is insanely fast (much more than SFTP over Ethernet) but I haven't seen one with USB-C plugs.
Or if you really need USB3 for achieving the maximum speed possible - I would like to find an external 2GB disk with USB3 wiring.
If at least one of your PCs is a proper computer (not laptop/mini-PC with almost all of PCI interfaces just stubbed) having at least 1 free SATA slot then just take the disk from one PC and connect it to another.