As the title says, is there a Siri command or shortcut to play my Apple Music library starting with the newest added song?
Here’s a shortcut I made a while ago. It plays the 20 most recently added songs. You can modify that number easily though
https://www.icloud.com/shortcuts/defac9215af24cda9e0123bdbc9cc75c
You should have a playlist already in your library called “Recently Added” and can have Siri or a shortcut play said playlist. I’m not sure how far back that playlist goes compared to what you’re wanting, so if you want to customize it more, you could setup a smart playlist to add all new songs to.