My first thought while reading your post was how far your speakers are from the front wall; a small adjustment in distance can make a big difference in bass response - you've probably already done this but I thought I would mention it.
You don't mention which Schiit DAC.
Consider your DAC and streamer selections.
You said, "At times the highs are glaringly high and when I expect there to be gobs of bass, there just isn't any to speak of."
Glare is an issue I've had with a few DACs and I had to spend more on a better DAC to get the results I wanted. Since you indicated the DAC and streamer were "placeholders," perhaps that may be the best place to spend that $2000. (Or part of it, anyway.)
I would try to audition a few DACS in your system. You may be pleased with the results both at the high end with less glare and by the better bass response.
Good luck!!
Tom