Like @rbstehno I was disappointed to find out that I could not stream Amazon music files to a UPNP renderer. I worked hard to get off of USB and that’s a deal breaker for me.

Yes that’s lame - but marginally excusable: AMHD is relatively new and doesn’t have much tenure yet out in the 3rd-party device/software environment, let alone the open-source audio ecosystem. But given Amazon-as-vampire-squid it’s hard to imagine any other approach other than one that benefits their businesses/services first. Short answer: don’t expect parity anytime soon with Tidal and Qobuz in support of the broader open-source audio community.

AMHD ’lying’ about HD is also lame. So are its feature and UX shortfalls. Simple example: no user-facing feature to create ’stations’ from artists. That problem was solved years ago by the competition - and has been missing from Amazon Music since at least 2014.
 Perhaps the best streaming I have experienced. Still not up to my SSD and that's a deal breaker.
So I have downloaded the Amazon Music fke the .99 a month for 4 months. I cant find any mention of HD within the app nor can I see what the songs actually are. Am I playing lossless already? Frustrating. I am using android, anyone have some tips? 
Make sure you sign up for HD service and not the regular one.

Their mobile app is not that great in showing track information, you are correct it doesn’t say if it’s “HD” or “Ultra HD”. I mostly use my Bluesound Node 2i and so far everything I have played is CD quality or 16 bit 44.1k, I have not seen anything better than that yet.