I have lots of albums in my Apple Music Library (some matched by Apple Music and most added directly from Apple Music to my library.
If any of those albums are shown in Apple Music (not my library) as being available as Lossless or Dolby Atmos and I select to play the album from my Library (not first looking for the album's listing in Apple Music), will it be streamed (I have not downloaded any tracks to my iMac) in the format that was available when I added it to my library or in the "upgraded" format of either Lossless or Dolby Atmos. I have Dolby Atmos set to Automatic and Lossless selected for Download and Streaming in the Music App preferences.
If any of those albums are shown in Apple Music (not my library) as being available as Lossless or Dolby Atmos and I select to play the album from my Library (not first looking for the album's listing in Apple Music), will it be streamed (I have not downloaded any tracks to my iMac) in the format that was available when I added it to my library or in the "upgraded" format of either Lossless or Dolby Atmos. I have Dolby Atmos set to Automatic and Lossless selected for Download and Streaming in the Music App preferences.