Nvidia Inspector cli with parameter -setFanSpeed:0,80 ( 1st value is the number of the card 0,1,2,3... , second value is the fixed fan speed in percentage ) , you can use also -setTempTarget:0,0,70 , -setPowerTarget:0,70 if its working for your purpose.
example : nvidiaInspector.exe -setFanSpeed:0,80 -setFanSpeed:1,80 -setFanSpeed:2,80
This do the same as set fixed fan speed in MSI Afterburner , as for fan curve there is no such functionality for now.
The problem with setTempTarget is that instead of increasing the fan speed as much as possible it will start throttling the GPU. Why the hell Nvidia thinks this is what people would want I have no idea..
And yes, I'm aware how to set a static fan speed.