I use Tidal on my iPad all the time, and I do indeed select "download for offline listening" all the time, she can do that with both albums and playlists. Do you have a Tidal family plan or whatever it is, that includes Claire? I do that all the time -- purchase via Bandcamp (just to support the artist directly), but then listen via Tidal (because it's easier, and I do most of my listening via Tidal all the time). That said, Love is the King doesn't appear to be on Tidal yet, so...never mind. Sorry.
I have Cubasis, so when I try to open an mp3, it tries to open in Cubasis, so I should probably just stop talking.
Oh, look, there's a foobar2000 app. That's what I am doing.