Floorstander reco given a few criteria...

OP, just a P.S.
The Music Room is used and gives 14 day trial. They verify that all products work. They’re great to deal with. Trying in your own space is crucial.
Crutchfield has free shipping and very inexpensive returns (e.g.$10 for 160lbs of floorstanders). They carry some very good brands, including Revel, Focal, Dynaudio, Wharfedale, Klipsch, KEF, Martin Logan, and more). Their open box deals can be amazing. I used to associate them with only having mid-fi or lower end stuff, but that is not true. Amps: also have some good ones: Anthem, Arcam, Cambridge, McIntosh, to name a few.)

What system sound and performance characteristics do you value most, and what would you most like to improve upon over what you have now?

I like detail and separation. Right now the sound is kind of hollow and compressed in a way. All the notes are there but they aren't crisp and like distinct or spaced out, if that makes sense. If there was a goal it would be warmth and distinction or space.

Anyone have experience pairing the QS mid monos with the Wharfedale EVO4.4 speakers? I can't find a shop near me to audition them, but I've seen some pretty good reviews. I might just order a set from Crutchfield and a set of the Klipsch Reference Premiere RP-8000F or the Heresy IV and see which one sounds better? Any thoughts on what to expect? Feelings on either manufacturer/line? Also intrigued by the Definitive Tech BP-9040 bipolars but I have no experience with this brand or design.

Underwood HiFi is running a good sale on its LSA speakers here.  They don’t have their LSA-20 Signatures listed, but if they’re on sale too I’d guess they’re somewhere around $2500/pr (that may also include free speaker cables).  Certainly doesn’t hurt to ask, and they offer a 30-day trial period.  There’s also a McCormack DNA-125 amp for sale on eBay for $1100, and pairing that with the LSA speakers would very likely be a killer combo that pushes all your buttons hard.  Just a thought given your preferences, and best of luck in your search.