This, unfortunately for this forum, is a piece-of-string question. Both of the DACs you mention are regarded highly but the final sound quality is going to depend on your listening room/speakers/cabling/power/amp/interconnects, and then we get onto your hearing. Both DACs will work with Volumio as Volumio is just pushing bits over an interconnect, it’s not actually controlling these off-board DACs. Best anyone can say is try them both (assuming you have a tame dealer) and go from there. An enjoyable quest, I think…
Im using dietpi with roon bridge and squeezelite and shereplay. Allo digione with pi3 connected with bnc to my schiit gungnir s/d Dac. Result is absolutlly amaizing!!! Compered to Mytek Brooklyn 2000 us$ dac, difference is so minimal, I prefer my gungnir which I wanted to sell but not now after I got Allo digione! Gungnir doesnt have mqa and dsd, but who need it?