Most RX 580s require a single 6pin or single 8pin. I don't know what gigabytes "normal" RX580 is, just post the model.
No GPU takes a 4pin for power. A 4pin or 4+4pin on a PSU is usually for CPU power, it plugs into the motherboard.
So if i connected a 6 pin to that card i could run games like battlefield 1 , rainbow six siege, far cry 5 without the PC restarting because the Card doesnt have enough power?