After updating your MacBook Pro to Sequoia, you can find your original music playlist by opening the Music app and checking the Library section where your playlists are usually stored. If your playlists don’t appear right away, make sure you're signed in with the same Apple ID and that the Sync Library option is enabled in the Music app settings. If you had iCloud Music Library or Apple Music, your playlists should automatically sync back. In case they’re still missing, you may need to import them manually from a backup using the “Import Playlist” option in the File menu.