Spotify streaming from pc

I need a little advice and or reassurance here.  I am streaming Spotify Family Plan Premium from my pc, via ethernet cable (due to distance), to my Oppo Sonica DAC which feeds my integrated amp and speakers in my listening room.  I have the Sonica app downloaded on an iPad, on which I can control what is being played, however, I have no audio quality adjustments available on the iPad/app.  It sounds okay, however, not nearly as good as Tidal and I am also not able to make any sound quality adjustments on the Spotify website at the pc either - as I could with Tidal.  Do I need the Spotify app on the main pc or not?  Is this just the way it is going to work or am I even doing this correctly?  This is the way I stream Tidal and it sounds great!!  Thanks for all help and advice!
Thanks hdm and henry00.

I gave up using the horridly frustrating and unsupported Sonica streaming app and bought a Bluesound Node. Holy crap I didn't realize streaming was supposed to be this easy LOL.  I still use the DAC in the Sonica because it sounds better (to me) than the Node DAC. 
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320kbps is the highest streaming quality you can get from Spotify. You may want to try adjusting the bitrate, sample rate, audio channels etc. of Spotify songs with the assistance of AudFree Spotify Music Converter. Apart from this, you will also download high quality Spotify music for free.