Are your temps reading correct at the hot end? My 24v E3D V6 Hotend heats to 300deg c in less than 45 seconds. If the thermocouple wasn’t reading right and it overheated, it would be a pile of molten slag with minutes.
Your temp reading (at the hot end) should increase rapidly once the heater turns on. If you don’t see that at the controller you may have a thermistor issue.