Big fan of Feishin!

For iOS I’ve always used play:Sub, but will give Amperfy a try!

Navidrome uses the Subsonic protocol to provide it's playlists.

You can use that to import to Symfonium, for example, but it won't stay synced if you make a change at one end or the other. You can reimport in Symfonium but it's still pretty messy and not very useful if you want to update your playlists on the go.