Sonic studios’ s Amarra Play is the best for hifi output to an external DAC, I prefer warm tubey sound and Amarra has always delivered on that front for both ios and desktop. There is no listening fatigue for me, you can log into Qobuz or Tidal and stream from there, play local files, or play your personal DRM free music from apple music(un-tested). There is a parametric equaliser with presets. It also doubles as a remote for the desktop app that supports DIRAC. Amarra has always kept the interface basic but the sound is something I have always returned to despite that. https://www.sonicstudio.com/amarra/amarra_play.php