The answer is supposed to be easy; it's "you need to buy one of those really expensive USB-C Thunderbolt 3 cables, because those cables—the ones that do everything—are supposed to be the only type of USB-C cables."
USB-C cables are supposed to be universal, i.e. have all the features, all the time; and thus, USB-C cables should (in 2019) be very expensive. Any USB-C cable that isn't very expensive (in 2019) isn't following the standard.
USB-C cables are supposed to be universal, i.e. have all the features, all the time; and thus, USB-C cables should (in 2019) be very expensive. Any USB-C cable that isn't very expensive (in 2019) isn't following the standard.