Lots of opinions here but my .02 is this… the 880 is just fine on the liquid spark zen dac stack and does the technicalities of the 880 justice imo and the warm nature and slight roll off in the treble area make it a good budget pairing for the 880.
The asgard 3 is an improvement overall (and also pairs well here with the zen) and has probably enough power as the 600 ohm would ever need (though I can’t confirm that) and the 3D presentation the a3 has is really nice with the soundstage and imagining capabilities of the 880… it also leans warm which is again nice imo with the 880
The darkvoice is my favourite pairing personality giving the soundstage and imaging space to play with but adding some warmth and body on top of that but lacking some of the detail retrieval of the Asgard 3