I see what you're saying here. Thing is, that's not a new skill for me. I have plenty of control over volume and expression with my right hand. I've gained that from decades of bass fingering and plucking, cello bowing/plucking/col legno, etc. Including palm muting on the bass.
What I lack on the right hand is:
1. A really good feel for the gap between strings, since they're so much closer; hitting more strings than I intended is exaggerated at gain.
Like, if you barely brush the wrong string with the pick without gain, it's not really going to be audible if you're hitting the strings you intend more forcefully. At high gain, every little tiny mistake like that is going to be as loud as the things you meant to do -- the result of dynamic compression at those levels.
2. Palm muting techniques at high gain are really a whole different technique from what I do on the bass or with a clean guitar.
Also, more to the point, palm muting's not a habit I want to gravitate to instinctually. It's a capability I want to deliberately train. That's what exercises are for; training your hands into flexibility and skills that you can use, or not use, at will.