Two cables can look identical and differ by 200 watts and 79 gigabits. Nine specs separate them, and spec 5 is why your 240W charger crawls.
USB-C is only the shape of the connector. Speed, wattage and video support are all separate features a maker can leave out and still call it USB-C.
The cable bundled with your phone is usually USB 2.0: 480 Mbps. That is fine for charging, and painfully slow for moving video off an SSD.
A plain USB-C cable carries up to 3 amps, about 60W. That charges a phone fast but will not run a big laptop at full speed, no matter the brick.
Anything above 3 amps needs an e-marker: a tiny chip that tells the charger what the cable can survive. No chip, no high-current charging.
Extended Power Range pushes USB-C to 48V and 240W, but only over a cable with an EPR e-marker. A 100W cable will not do it, even with the right charger.
Driving a monitor needs DisplayPort Alt Mode. Charge-only cables skip those high-speed lanes entirely, so the screen simply stays black.
Passive 40Gbps cables top out near 0.8m. Beyond that you need an active cable with electronics inside, or the link quietly drops to a slower mode.
USB-IF certification logos on the packaging name the real speed and wattage. Uncertified cables skip the testing that stops them cooking a charger.
Charger, cable and device negotiate down to whatever all three support. One cheap cable caps the whole chain, which is why fast charging silently stops.
One certified 240W, 40Gbps cable handles the phone, the laptop and the monitor. Label it, and stop guessing which drawer cable is the fast one.