He has a 600 watt PSU now....that should be fine.  Extra cooling will probably help only if the GPU gets too hot.  I have an RTX 2070, 3070, and 4080 12G.  I like to run with it locked at 60 FPS.  The 2070 cannot do this.  The 3070 will, but creates blast furnace type heat.  The 4080 doesn't...