Direct USB-C to USB-C extensions are explicitly forbidden by USB standards for safety and performance reasons because they defeat built-in safety mechanisms. All USB-C to USB-C cables should support 60W charging, but there are also cables that support 100W and 240W. USB-C chargers and devices identify a cable's capabilities by reading what's known as an electronic marker (e-marker) inside the cable that explicitly reports >60W charging and/or 5Gbps or faster data transfer capabilities. A USB-C charger will first read a cable's e-marker and adjust its power output based on what the connected cable's maximum charging capacity is. The problem with extension cables in general is that they don't (and can't) have an e-marker, since by design, normal cables only have one addressable e-marker. Therefore, neither the device nor the charger is aware of the presence of an extension. If your USB-C to USB-C extension only supported 60W, and you connected it to a charger/device combo that could do 100W or more, you could start a fire. This failure is particularly insidious because it can potentially lull the user into a false sense of security; everything might work as expected until they change something, like upgrading the charger, and then it could fail catastrophically. Another reason extension cables don't work well is that the signal integrity requirements for USB-C's higher transmission rates are very strict. Believe me when I say that cable makers would make longer cables if they could. (stolen from reddit cause it's explained better and faster than I can) you do you, just so future readers know