The Schiit DACs are punchy, yeah. And for the longest time that was what I prioritized most in my chain. If that’s what you desire most, then stick with a Schiit DAC.
But when I reviewed the Yggdrasil and compared it to DACs in the $2-4k range, I described it as such:
Schiit Yggdrasil A2: The equivalent of audiophile junk food. Not accurate, not detailed, almost excessively too wild, fun, and fat-sounding that it can make the other DACs sound boring. Truly the American hifi experience.
And honestly to this day I still feel this way. The Schiit DACs sounds warm, fun, fat, and punchy. If that’s what you want, then more power to you. But HE-6 4S is already plenty punchy and fun that I feel like using a Schiit DAC actually holds it back a bit from its full technical capabilities.
Unrelated note: punchiest headphone setup I can think of is probably Yggdrasil → A&S Mogwai SE → 2020 Focal Utopia. I’m sure @Draaly would approve.