A cable is a cable is a cable.
You guys are acting like the USB-C is something special, but it is just the format of the cable. In order to be USB-C, it has to follow the same guidelines as any other USB-C cable. So what you are looking for is details about the actual product that is attached to the USB-C.
You need to supply 15v at 3a to charge the switch properly. Under that will still allow the device to charge, slowly, but under certain conditions. The main condition being you won't be able to play while charging it at the same time as you will be using more energy than supplied by the powerbank/charger. If you go over the recommended specs, you risk frying your device. (Or blowing it up, ala Samsung.)