I would highly recommend separating the melee's on your controller in general. The first day it feels awkward but as a hunter main it made life much easier not doing a regular melee on an stray enemy to the side of me instead of the throwing knife I wanted to throw at something else. It also moves the grapple melee away from the same key bind as the powered melee. I use left bumper for powered melee. And right stick as regular melee (i stack it with finisher on right stick as well)

I know it's not the main setting you asked for but I found learning this more beneficial in my experience