I have no idea how you're even supposed to legitimately decode Atmos from Apple Music. Does an Apple TV support Apple Music, and if so does it deliver multichannel sound over HDMI?
I've sought out some "Atmos" versions of popular music on Apple Music with my Mac, and listened with headphones through a good D/A converter, and the results are bad. Entire parts (background vocals, for example) are sometimes drastically suppressed and transients (like drum hits) are sometimes accompanied by extraneous sound. These artifacts vary widely by recording (although it's possible that they're often present but I only discern them on songs I know well).
I've sought out some "Atmos" versions of popular music on Apple Music with my Mac, and listened with headphones through a good D/A converter, and the results are bad. Entire parts (background vocals, for example) are sometimes drastically suppressed and transients (like drum hits) are sometimes accompanied by extraneous sound. These artifacts vary widely by recording (although it's possible that they're often present but I only discern them on songs I know well).