I finally sold my Utopia. I just wasn't using it enough. Yes it was very impressive, but it was far too fatiguing, and a $4k headphone that you could only use 30 minutes at a time wasn't worth keeping. Sadly, I think the Clear falls under the same category too, I can listen to it for longer than the Utopia (1-2 hours) but still it's not an all-day headphone. I don't know what it is about Focals, but they seem to irritate my ears in ways that other headphones don't.
Regarding the DSHA-3F, it is a very transparent and resolving amp, and if you want to max out the Utopia's resolution, go with that. But it doesn't really change what the Utopia is. And you find the Utopia borderline, the Clear with the DSHA-3F is nearly as resolving (the highs are worse, but the mids and bass are similar) and definitely less abrasive.
You could also try a bit of EQ, the Utopia does have a narrow 6khz peak and exaggerates treble past 13-14khz by about 6db or so. But to me that only mellowed it out a little bit.
So, I think I'm leaving team Focal, since my ears refuse to cooperate.