Ah! You’ve falling into the trap. Not all USB-C Cables are the same!
Some are intended for charging with heavier gage wires and multiple contacts, whereas other cables are intended for data use and light power need. And lastly, some cables aren’t true USB-C but instead are custom by the hardware maker or as in the case of Apple they offer a super set of additional lines for Thunderbolt use.
You’ll need to either order the makers cable or locate the schematics to try to figure out what is going on. You’ll likely need create a breakout of some sort to test the lines as the contact pitch is so small it will be hard to hold a meter prob on the contact or you may end up shorting things.