I personally returned my Magni 3 to Schiit in the first 2 weeks after buying it, as I didn't like it with any of my headphones.
The Elex are quite resolving, and I plainly hear hear the DAC as well as the amp. I've tried it with 4-5 sources and can easily hear the differences between each.
I'm mostly using the Elex with a FiiO Q5 portable Amp/DAC (XLR to 2.5mm adapter and balanced output), as I use headphones when I want a compact or mobile setup. The Q5 has a clean, neutral, noise-free, and well-defined profile, and the balanced output has strong bass extension versus the somewhat thin standard output. The source material remains in control either way, and this suits me as I tend to dislike deviations from the source.
Yesterday I used the Q5 as a DAC and ran the line-out into my Massdrop Cavalli Tube Hybrid (CTH) amp and listened for a few hours. This results in tube bloom, sparkle, and chime. Overall, the music is 'highlighted' at accent points. For most sources I don't need or want coloration, but it's a fun way to improve dead mastering. The CTH also adds faint background noise or 'haze' to the sound vs. the Q5 balanced output.