Soundiiz is supporting the import of LINE MUSIC playlists to other streaming services with the Share link provided by LINE MUSIC (available in Japan, China and Thai).
For that, simply go to your playlist on LINE MUSIC and use "Share" button to get an URL.
Then simply go back to Soundiiz, tab Playlists and use "Import playlist" button in top right of the interface and select "By URL". Then paste your URL and follow steps !