mod gpu bios for ubuntu

hi
i would like to switch from windows to ubuntu os,but as far as i know it is really difficult to control and adjust gpu core voltage and fan speed there.my question is ,how i can edit my rx470 bios using polaris bois editor to first set the fan speed to 48% (all the time) and reduce core voltage about 80 mv.(my ideal fan speed and gpu volt in windows)
i don't want to risk bricking my gpu.

thanks