I'm in a Deezer HiFi trial since the price dropped. Really like the android interface but streaming options are limited.
I want to add room correction also (homebrew PC, optical in/out, so that becomes even more difficult.
If you want to use the native app & HiFi, the only viable option is Chromecast (audio) which supports HiFi. Works fine, except no gapless playback. Using a classic Chromecast, HiFi shows up on the screen (in the album art) - chromecast has optical out.
Other tests I did:
* An old panasonic ALL-1C streamer (Qualcomm Allplay) supports Deezer via a service called "airable". Interface looks good, is fast, I have optical output. However, absolutely no way to figure out if I'm streaming 320kbit MP3 or HiFi.
* BluOS should work, but all options are expensive. Not sure if the interface (android) is any good
* MusicCast - didn't test the (android) interface but I read good things. Yamaha supports Deezer HiFi so NP-S303 could be a good option. Again, hard to know it's actually FLAC streams and not MP3.
* The hardest test - I'm running Logitech media server/squeezebox which supports Deezer 320kbit. I was able to hack the Spotify plugin so that when selecting a track there, a matching track (FLAC) from Deezer is streamed instead. This is based on non-official API though (reverse engineering of the web interface) - writing a full plugin is way past my capabilities, but would be ideal for me.
So I'm not sure yet to go Deezer instead of Spotify. I feel Deezer has the best track selection for my needs, and is cheaper than Qobuz/Tidal. I don't want to support Tidal so that's not an option for me.