The BluOS platform has Amazon Music as a native option within the app…not a casting one like Spotify or Tidal Connect. The Node N130 is the device to fulfill your objective. But if all you want is Amazon Music the Echo noted above is more economical, although its onboard DAC may not be as well implemented.
Amazon Music High Definition and Ultra High Definition Equipment Requirements
My goal is to use my late-model iPhone to stream music from Amazon HD/Ultra-HD through some sort of DAC and then on to my stereo (old McIntosh with Bozak speakers). I see that the upper transmission rate specified by Amazon is 24 bit/192 kHz. Am I correct in assuming that a DAC such as, for example, the Schiit Modi+ , will allow me to accomplish this goal? For reference, here is. link to specs on this DAC: