Honestly, power over USB is limited by the technical specifications. So the gauge of wiring in USB cables, connectors and plugs matches that specification (to barely meet it). Type-A and Type-B connectors are supposed to be 5V @ 2A maximum. The 28-gauge wire typically found in USB cables is good enough to carry 500mA at 5V. You're looking for a cable which uses at least 24-gauge for the pair of power wires. (This is why I'm always reminding that a shorter cable is better.)
USB Power Delivery
Note that you can solder some larger-gauge wires to your Pi's motherboard if you want to bypass these limitations.
Acceptable loss calculator says 5V @ 3A @ 1/3 meter @ 1% loss = 18 AWG (1% loss of 5V input = 4.95V output which is well above the 4.64V threshold)
Some 1-foot USB cables then:
21 AWG (2% loss of 5V input = 4.9V)
23 AWG (3% loss of 5V input = 4.85V)
24 AWG (4% loss of 5V input = 4.8V)
It's possible that their calculator is buggy, though.