Hi TomImler,
We see you have some questions about using the Shuffle feature via Apple Music, and we'd like to help. To get the support that you're seeking, check out the link here: Library: Browse and play your music on Apple TV - Apple Support
To perform the recommended troubleshooting steps via the link above, complete the steps in the section titled "Shuffle items in a category or genre."
1. Open Music
on Apple TV, then navigate to Library.
2. Navigate down to highlight a category or genre.
3. Select Shuffle at the top of the list, then select Play.
4. Siri: Say something like:
* “Play Bastille shuffled”
* “Play ‘More Rain’ shuffled”
We recommend the steps above because they will show you how to browse and play your music via the Apple Music app.
If you’re still experiencing the same issue, try reaching out to Roku for continue support.
Roku Support
Thanks for using the Apple Support Communities.
Cheers!