so for Apple Music, how does one listen to greater than 48 kHz on other than an Apple device?
That’s the problem - you can’t. Apple is a closed ecosystem. It’s why you can’t access your Apple Music library on Roon and other music management/operating systems and streamers beyond AirPlay. But if you have Apple TV, Apple Music, an iPhone, and Apple headphones you’re good to go with Hi-Res lossless. This seems both intentional and smart because to some extent it encourages consumers to buy into the ecosystem; not just their new device/phone.
The only workaround that I’ve found is either having an Apple or Android phone/tablet, Apple Music, and outputting to a DAC (AQ Dragonfly for example) into an amp.
Soundiiiz, which is generally free, can help you transfer library’s between the major music services if heavily invested in Apple Music.