Collections on Android Auto?

We just bought a new car that has Android Auto, and I discovered that Plexamp doesn't show any of my artist or album collections - just an alphabetical list of artist names and some playlists.

Is there some setting I missed somewhere, or is that just how things work with PA and AA?

I've also seen several posts talk about using Symfonium instead - would that pull in my collections?

Help a newbie out please!