I have the Sonoma 14.2 Release Candidate and Apple has changed the way new playlists are created in the Music app. When the File > New > Playlist menu item is clicked, or Command-N is pressed, a panel will display allowing you to enter a name and provide artwork for the new playlist.
I dislike this. But there doesn't seem to be a way to shut it off.
Happily, creating a playlist with AppleScript hasn't changed. Here's a very simple script that when run will just create a new playlists named "Playlist" like it used to be.
You can save this in Script Editor as a ".scpt" (Script) file in the ~Library/Music/Scripts/ folder and even give it a keyboard shortcut.
A more advanced version of this script, "Name New Playlist From Selection" is explained in this link. It was originally written for iTunes. But just substitute "Music" where "iTunes" appears in the script and it should work fine.