BEST SPEAKERS AT A REASONABLE PRICE

I like the idea of active speakers as they will sidestep the issue of amplifier adequacy. While I believe most actives are class D, my understanding is since they are voiced with the specific speaker in mind you get more positives out of that synergy than you give up in the arguably inherent weaknesses of class D. LS50s also come in active configuration with direct streaming and DAC built in. Not listened to them myself but heard good things.

I'm in about the same budget range as OP, although I've actually lowered my dollar amount seeing what's available out there! I started this hunt a couple of months ago looking at the Monitor Audio Silver 300, but in reality these are too large for my space - even though they're much smaller than the speakers I'm seeking to replace.

I like the KEF R100 for a warmer sound but they are clearing out the R500 floor standers for a good price. Heard good things about several of the ones mentioned. But you have to listen for yourself. There are so many good but different sounds to the same source. Also may want to consider Focal and Dali.

The R500's are 50% off right now, and it looks like that's my final choice. The size of the drives is right for the listening space. And $1400 (with lovely 10% CA sales tax) puts it in a nice spot. The R5's are only $2k, but the build quality isn't as high as the older ones. Heck, if the OP has the space, the R700's are $2k/pr. I've heard some people prefer the R500's because they blend more seamlessly with the UniQ. YMMV.

The Dali Oberon 5 look interesting but perhaps a bit small, the 7's on the other hand might be perfect for the OP. Cool design. Plus, they're not vinyl wrap like the Zendor.

I've always respected Focal speakers, and some fantastic prices have popped up briefly on the 948's. In fact, there's a pair at A4L right now in piano black for $2500. Probably because it's their last pair. NEW! That's a crazy great price.

Used KEF 104 @ about $500 pr.  

Reasonable price? Find yourself a vintage pair of DCM Time Frame speakers 500, 600 or 700, you'll be n pleased. Roughly $350-550 tops.

Open baffle speakers, like my recommendation (Emerald Physics KCIIs) don’t need no stinkin center channel

The upgraded KCIIs with carbon fiber drivers is available for $1999, delivered.