DSD DAC/Headphone amp for iPhone?

I have Sennheiser HD800 and Beyerdynamic Amiron headphones. What is your recommendation for the best combo DSD/DAC headphone amp out there? I want use my iPhone X as my hi res DSD playback device using the currently installed Onkyo HF Player app that plays DSD ( .DFF and .DSF) files.
Is there such a plug and play Portable converter amp? If so what’s the cat’s meow? Money no object.
It must be truly portable. Ie. Battery powered/chargeable.
I also have Beyer Amiron headphones but use Android. It should work with most portable usb dac's even with iPhone. I use an Audioquest Dragonfly Black and an iFi Nano. iFi has some new models like the Hip-Dac that looks interesting but if I would buy a new one I would go for the DragonFly Red or DragonFly Cobolt depending on how much I could spend.


Forgot to say that if you can spend more money the Chord Mojo (maybe with the Poly) often gets good reviews.


Their new 2go and Hugo2 is according to John Darko even better but costs $3500.
Another potential option is the xDuoo HD05 Plus.  Lots of power and good battery life, and it gets very solid reviews for sound and value.  A bonus (at least to me) is that it gives you the ability to swap op amps so, along with the four different onboard digital filter options, you can custom tailor the sound to your liking.  Best of luck.