Tone and pc setup question

Hello, I currently use a katana mk 2 with a les paul but I have a problem. A lot of the distorted tones that I download to my live sets sound horrible when Im playing through the amp. They sound great when I listen through my pc though. Through a little research I have down something about the les paul and the katana cause distortion to sound real muddy. I am curious if anybody has run into the same issue and how they improved distorted tones. I also use audacity to listen to myself with headphones but there is a very very slight delay that I cannot figure out how to get rid of and throws me a little off. I run the katana directly into my pc with a usb cable. Any suggestions would be appreciated!