From my experience the HD/Ultra HD badges only appear when playing Amazon Music directly from the Sonos app, not from the Amazon Music app.

Thanks for your response. Re "badges only appear..." comment. My very limited experience tells me that the badges seldom appear in the Sonos app for songs I know are HD/UHD. However, if I used the AM app the badges show up on every HD/UHD song. So...I guess what I'm asking, is my music from the AM app broadcasting in HD on my Sonos system? Today is only my second day with AM and Sonos, so I haven't really had enough to see if I "hear" HD from the AM app.

Is there a way to ask Sonos directly from this site?

Not easily, no, this is a community site, and not a ‘talk to Sonos Support’ site. There are a couple of forum moderators, but they aren’t really Sonos support, although they do have some great knowledge and abilities to read diagnostics, when they can. Your best bet is to call Sonos Support directly to discuss it.

I think the audio format to Sonos devices from Amazon App ‘Connect’ is up-to 16/44 Flac (HD) and I think iOS Airplay2 supports up-to 16/48 ALAC (HD) and the Sonos App AM Service format is up-to 24/48 (Atmos) Flac (UltraHD) depending on the source and type of Sonos speaker/group targeted.

Only the latter service displays the audio format in the Sonos App - I’m not sure that the Amazon Music App display is entirely accurate, as it may just relate to the iOS device internal speakers that their App is installed on, but maybe check that with Amazon, plus these things tend to change with each new App update.