I can't tell how much low end thud you have since I'm on my latop speakers...but you just need to adjust your right hand position on the bridge (or near the bridge, wherever is right for you) so that you find that sweet spot where you get a good blend of string sound and mute sound.
If it seems to dull/boomy...you may be diggin in too hard with the mutes.
AFA your mix...the thing that stands out for me is that your guitars have a decent amount of reverb/ambiance, and your drums have basically none...so there is a room/space disconnect between the drums and the guitars for me.
Either pull some back off the guitars or add some to the drums...or a little of both. Same as with the palm mute, find a good balance point.