Another thing you might try

. I notice you are using treatments. (imho) there is a direct correlation between room treatments and the internal dampening of speakers. So what I see is a heavily treated rear wall using heavy internally damped PMC speakers. Since the treatments are already up go into your PMCs and pull out all the internal stuffing. Start with all of it. Do not listen too loud but figure the best internal dampening amount by putting more back in as you go. This will help with the intensity or tension in the soundstage..lightens it up. Makes it sound more floaty ....lol.
The below quote is silly and only leads to (if you are lucky) parallel moves compared to the BP 26. The BP26's power supply is overkill and its outboard. Great for the volume control.

The volume control on that pre amp is excellent for dialing in good precise volumes. You do not want to get rid of that.
"I was told by experienced audipophiles that Bryston is very transparent as well as PMC. It doesnt mean analytical or cold, but direct (what "in", that "out"). I was advised to have some colored component on the path like tube pre amp, multibit DAC or less resolutive/more forgiving speakers".