I reached a slight different conclusion
DAC: BTR3 (same choice as yours)
Headphone: "Etymotic ER2 XR" $100
The Negative? You have to make ONE more purchase. You need to purchase COMPLY tips as the stock ones don't last long.
These headphones are so sensitive (15 ohms), that you can easily power them off a smartphone alone. And, you can't even turn the BTR3 to full volume.
They beat every Chi-Fi underneath it, and the next step up is likely the $300 range.
I still purchase other headphones, but I don't any other IEM's anymore.
I used to be like you purchasing, and chasing every new $50ish Chi-Fi IEM that came out.
Etymotic ER2 XR ... $100
You NEED to purchase COMPLY tips to go with them or you will think I'm crazy
Detailed, vocal forward, with a touch of clean bass.