I am very happy with the sound of my system at this point, so I’m not sure if the DAC needs to be improved on. What I am looking for is to hear those background subtleties in the music a little more pronounced.
What a beautiful bay/lake view from your room. Having such a relaxing room is a huge plus, I have the same. I like the above recommendations for new power cords but think that something like the Zavfino Fina OCC power cable that sells in the $350 range would do the trick.
But being very happy with your sound and just wanting a little more detail, I would not think twice about the purchase of a Schiit Lokius 6 band graphic equalizer for about $300 and ever so gently boost your treble and upper mids or whatever suits your preferences.
Someone has voiced every component we own, with an EQ you can subtly tailor that sound to your preference. Then, if you still feel the need, you can consider a bigger component change. Just my humble opinion.