Since the design philosophy behind USB-C is "it must always
seem as though it
should work", I think we'll need something like the old "tube testers" a few of us still remember.
Decades ago, when your TV was behaving badly, you would take the back off (unplug first!), pull the vacuum tubes out, and take them in a bag to the nearest convenience store. They had a "tube tester" the size of a washing machine. You'd plug each tube into a connector, one at a time, press the "test" button, and the needle on the dial would show good/poor/fail. The body of the tester was a cabinet containing replacement tubes you could buy (and which you could even test right there).
We might need to start using USB-C cable testers. Plug in a new cable, get a good/poor/fail analysis of each potential USB-C feature, then you mark your cable yourself with some labeling scheme.