@Tomibeck sure, but it’s not exactly MusicCast, it’s actually a channel of the yamahareceiver binding.
So it will only work with a receiver capable of communicating with the legacy protocol.
What I found is you can add favorites with the MusicCast app to your receiver, including Spotify playlists (just use the context menu & add to a favorites slot while you’re playing it):
Then using an item linked to the “netradiotune” channel, like this:
Number Yamaha_NetRadio "Net Radio" {channel="yamahareceiver:yamahaAV:xxxxxxx_xxxx_xxxx_xxxx_xxxxxxxxxxxx:netradiotune"}
You can send a playlist number to the item and it will tune your receiver to the corresponding playlist, including those which “rotate” once a week like Discover Weekly and Release Radar.