I'm running the 0.9.7 beta, I'm not sure if this is a regression with the new UI redesign or something that has never been present as I haven't used any pre-redesign release.
The only way to add content to a playlist as far as I can tell is to add songs individually; the menu that pops up when long-pressing on an album only offer options for adding the album to Next Up or the Queue, but not to a playlist, and same for the long-press menu on playlists. I'm not familiar with any other method of adding an album or playlist to a playlist so if that option does exist somewhere it is probably not in the best place for user experience IMO.
I personally don't have a need for adding a playlist to another playlist, but I do somewhat often want to add entire albums to playlists. Adding collections of songs, be it albums or playlists, to a playlist is functionality I've seen in other music apps and was expecting to see in this app too. Adding each song individually to a playlist out of a 10+ song album is tedious but doable, but to do the same with a playlist with potentially hundreds of songs is unreasonable I think. The jellyfin web UI supports adding albums and playlists to playlists so it would seem reasonable for the app to support the same.
I'm running the 0.9.7 beta, I'm not sure if this is a regression with the new UI redesign or something that has never been present as I haven't used any pre-redesign release.
The only way to add content to a playlist as far as I can tell is to add songs individually; the menu that pops up when long-pressing on an album only offer options for adding the album to Next Up or the Queue, but not to a playlist, and same for the long-press menu on playlists. I'm not familiar with any other method of adding an album or playlist to a playlist so if that option does exist somewhere it is probably not in the best place for user experience IMO.
I personally don't have a need for adding a playlist to another playlist, but I do somewhat often want to add entire albums to playlists. Adding collections of songs, be it albums or playlists, to a playlist is functionality I've seen in other music apps and was expecting to see in this app too. Adding each song individually to a playlist out of a 10+ song album is tedious but doable, but to do the same with a playlist with potentially hundreds of songs is unreasonable I think. The jellyfin web UI supports adding albums and playlists to playlists so it would seem reasonable for the app to support the same.