The cable decides more of this than the charger does

A cable rated at 240W attached to a 90W charger does not produce 240W. It means the cable will never be the limiting factor, which is a genuinely useful property and a completely different claim. Of every pair of numbers on this site, these two have the least to do with each other.

The way a cable declares its capability is a small chip inside the connector, an e-marker, which tells the charger what the cable can handle. Without one, a USB-C cable is treated as a basic cable and the whole chain drops to a conservative level. This is the most common invisible bottleneck in a charging setup: a capable charger, a capable phone, and a cheap cable quietly holding both of them back.

Wattage rating and data rate are also separate. A cable can be rated for high power and carry data at the slowest USB speed, which is fine for charging and disappointing the first time you try to move video off a phone. Listings often state one and stay quiet about the other, and where a listing says nothing, this site says nothing.

Length costs something too. A longer run loses more voltage, and while that is negligible at twenty watts it becomes noticeable at high power. A ten foot cable is the right answer for a nightstand far from an outlet and the wrong answer for pushing a laptop-class load.

A practical way to shop for this: buy the cable for the largest thing you own, not for the phone. A cable rated well above what any of your chargers can supply removes an entire category of mystery from your setup, and it costs less than working out which of five cables is the slow one.