Linestage types versus soundstage

A little background. I have been cynical about powered linestages in a digital system. If the impedance ratios are okay, what needs any gain or amplification? Isn’t “straight wire with attenuation” the goal? What’s all those components doing in there if it all ends up going through an attenuator anyway? Would such linestages exist if CD’s had been invented before vinyl? As I watched these products climb to $10K, $20K and beyond, it just seemed stranger—likened to a product that makes water wetter. Cynical, rational me.

But I still felt audio was an experiential endeavor, and had a tube integrated because I enjoy music played through it. I got the upgrade bug and bought the newer, bigger, better tube amp from the same great company, thinking I’d stay in budget by running my Benchmark DAC2 HGC straight into it.

So I did. Things are clearer and more extended…and the soundstage moved to the wall behind the rack and went flat. Let me say here that I have complete belief and trust that Benchmark products are at the top of their class. I respect their recommendation to place nothing between their DAC’s with HGC and the amp. Nevertheless, I borrowed back my old Pass Aleph P linestage. This line stage allows me to optionally add gain to each single-Mosfet channel that fronts a high-quality attenuator. I did that and the soundstage seems taller, but not back to the voice hovering-in-space of the tube integrated.

To summarize, I’ve gone from a tube integrated to tube amp driven from a very good DAC, and gone from EL34’s to KT88’s, and gone from single-ended to balanced, but the DAC and speakers are the same. Perhaps I’ve screwed up something else in the signal path. I wasn’t planning on adding another device, but it looks like I’ve crossed the Rubicon on tube-powered linestages, which I’ll judge on experience rather than thought. Still, some questions hover:

1) What creates soundstage and is there something about tubes that gives them this ability?
2) How is the signal leaving a powered linestage better than the incoming signal? I can answer that question for amps, phono stages and MC step-ups, but beyond "attenuated" I'm still conflicted on powered linestages.
3) Is there an argument that a lot of energy behind the signal going into the linestage attenuator can produce better results? If not, why does BAT have all that energy storage?
4) What new or used tubed preamp less than 4k will give me back that compelling 3D soundstage that extends in front of speakers without added bloat and syrup? New Backert, ZOTL or Van Alstine or a used BAT or AR?  I'd like one that doesn't create a lot of heat.
6) Should I leave things as they are and look to speakers to address the soundstage issue?

I’m going to AXPONA to see what’s out there.
Thanks for any advice or education.