I've been very happy with the Pro-Ject Pre Box S2 Digital DAC/headphone amp
https://www.project-audio.com/en/product/pre-box-s2-digital/
It won the “Best DAC/Headphone amplifier” award from EISA a couple of years ago. Swapping it from my office system into my living room system in place of a Bel Canto DAC 3, it held its own.