My experience is the treble is not shoved into your ear. There is distance so a cymbal sounds more is behind the singer. So correct depth to the drummers position. On edm high hats will be in line with the midrange and bass never making it disjointed. When I put back the 1266 on I didn’t like the treble for about 5 minutes. It was too much but not harsh. So the Solitaire has better soundstage and imaging then the 1266 IMO. Soft to me would be no sweetness or sparkle just sounding dull.
I think below the 5kHz region is where the dominating frequencies of cymbals and hi-hats are, so it is in that sense "not shoved into your ear" as you mentioned. But when you compare with Utopia back to back, it might sound soft. But this kind of comparisons are error prone as the human hearing is adaptive but the adaption is not happening in light speed. You listen to Utopia for 10 minutes and then listen to D8000 and it will sound warm. Then you listen to Empyrean for 10 minutes and then listen to D8000 and it will sound bright.
One really has to take time to appreciate what the gear offers.