This is how dwps muting works, with the hypothenar. You can see this in the “Pickslanting Primer Intro Lick” clip above - the pinky side of the hand is resting on the strings.
I’m using a “rotational” picking motion in that clip as well, so hypothenar muting still works while doing this. Of course, most “rotational” picking techniques aren’t really only forearm, so there’s a bit of wrist involved as well. Depending on the blend of wrist vs. forearm the contact point changes, but you can still use hypothenar muting in these blends as long as you don’t do the gypsy wrist flex and lift entirely off the strings.