Now, I'm confused.

+1 lpretiring

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In general, you need to treat your room in the dimension you are lacking. If you need width, treat the sides. If you need depth, treat behing speaker and listener. 

There are many factors to soundstage.  A cable, speaker placement, preamp, DAC, etc.  Happy Listening.

All recordings are artificial and many (particularly multi-tracked rock and rap) are far from the "sound of musicians playing in a room"! What many prize in a stereo system as "soundstage" is often an illusion caused by wall and floor reflections! 

Anybody remember the AudioPulse reverberation device? It allowed one to dial in various settings: "small club" all the way up to "cathedral"! It contained a two-channel amp to be connected to a pair of speakers behind the listener. And it gave surprisingly good results when used judiciously! This was back in the mid-70's before HT. 

The soundstage consists of width and depth. That's why room treatments are being recommended. Using absorbtion and/or diffusion panels will help shape the soundstage and focus the image.

Regarding a preamp, the Schiit Freya may be worth an audition due to the use of the 6SN7 tube, plus a return policy.