+1 for the casting option on plexamp to smart android TV.
All the well known music player like Deezer, Spotify or SoundCloud allow casting when you’re phone is on the same network as your TV (which is in my case linked to an amp and 5.1 Cabass speakers). The phone works as a remote controller and the sound can be played on our hi-fi system (I have some DTS musics that sound awesome in 5.1
).