Soundiiz supports importing Musi (iOS) playlists to other streaming services with the Share link provided by Musi (feelthemusi) in the app itself.
For that, go to your playlist on Musi (iOS) and use "Share" button to get an URL using "Copy Link".
The URL should like, for example: https://feelthemusi.com/playlist/snups1
Then, go back to Soundiiz, tab Playlists, use the "Import playlist" button in the top right of the interface, and select "By URL". Then paste your URL and follow the steps!
About the "Backup code" from the Musi app:
You can also copy your Backup code from the Musi app and go on Soundiiz to the left panel to connect your "Musi" backup directly to Soundiiz. We can retrieve all your Musi playlists and favorite tracks, ready to be exported as backup files, for example (text, CSV), and also to another music service!