"Amplify" LED-Controller to handle higher currents
If the MOSFET is up to the job and bolted to a big enough heatsink, it should work fine.

The series resistor R2 will need to be adjusted (probably way below 100 ohms).  Make sure the resistor won't be fried as well.  Use a high enough power one, maybe with a heatsink of its own.

There's no reason why a modest increase in PWM frequency won't work either.