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.
Thanks!
128x128rocketroom
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.

https://darko.audio/2019/07/10-more-thoughts-on-the-audioquest-dragonfly-cobalt/

https://ifi-audio.com/products/hip-dac/
Forgot to say that if you can spend more money the Chord Mojo (maybe with the Poly) often gets good reviews.

https://chordelectronics.co.uk/news/mojo-a-product-of-the-decade-says-darko-audio/

Their new 2go and Hugo2 is according to John Darko even better but costs $3500.
https://darko.audio/2020/04/10-more-thoughts-on-the-chord-2go-hugo-2/