An update:
USB files = much better
SLA = didn't mess with, just ditched using the phone all together
Time Alignment = night/day difference
Sub Phase = seemed to have helped
Sub break in = questionable but may have helped
Biggest change on the subs was simply diving into the x-over settings in the pioneer deck, and somehow with the TA applied, everything has just kind of come together. Finally at the point where I can actually hear vast differences in crap vs. well recorded songs.
Now the biggest challenge is simply finding good music that's timeless and well recorded, and not obnoxious.
I've been on a phil collins kick, and it actually DOES sound good:
https://www.youtube.com/watch?v=g1mSJpOBXFU&t=159s