Headphone Amp for Focal Utopias?

You might look at the Dennise Had ( of Cary fame ) Inspire headphone amp available thru Moon Audio as the Dragon, have had mine for 4 months and really love it. As soon as things get back to normal I will be selling off three amps that it has replaced, one being the Yamamoto H03, which is no slouch. My Inspire is driving Hifiman HE1000v2 most the time.  Enjoy the music

The Simaudio 430HA is the best headphone amp I've owned, and I've had many.  The Sony TA-ZH1ES is also very nice and includes a really good DAC if that matter.  There's a DAC available for the 430HA, but I don't have it so can't comment on it.

Both amps have a lot of power (not that you need that much with the Focals), lots of connection options, hi/lo gain switches, and very black backgrounds.

I have no experience with the other two you mentioned.

I've the Cayin Tri-Stack ( i-6 Series - amp, dac and dap ) .. very flexible and enjoyable setup

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I have Focal Clears, as well as LCD3’s. My favorite amp is the Woo WA5 - it is magic with every headphone. I also have a Woo WA22 which does great on the Focal  but prefers balanced sources. 
I am not a fan of pairing the Utopia with Sim - you need a warmer sounding amp as the Utopia can have a slight bite in the upper treble region. 
One other amp to consider is the Violetric V281 - lots of people with Focals like that pairing.

I use Focal Elex with the Simaudio 430 HA and it sounds wonderful.  I've only listened to the Utopia briefly, and not with this amp.  Definitely take into consideration what type of sound signature you prefer and find something complementary.  I've actually heard the 430 HA described as being "soft", a description which I don't agree with.  We all hear things a little differently.  I find it to be very detailed and neutral and a good match with all the headphones I've used with it including LCD-4, HD800, and Sony MDR-Z1R.