If in the USA
JBL 530 for $249 a pair currently
JBL 570 (small floor stander) $199 each, $400 a pair.
While I take a lot of measurements and love them, I assume you want some subjective feedback here.
Just did a comparison in my home between the JBL 530, Polk L200 & the ELAC DBR-62. While I can see the merits of a listen and understand some may really enjoy them, I did not care much for the ELAC DBR62. There is no chance they would be a long term pick for me. None. A very boring speaker that has bass bloat (bloat could be tamed with RC or a perhaps a different set-up) and a treble that just sounds so... fakey? I really wanted to like them due to the solid ASR rating/ H. score and rec but no.
The fairly pricey Polk L200 is similar to the R200, and actually the word is the R200 is "better". I greatly preferred the Polk to the ELAC so if the less expensive R200 is as good or better then I would easily consider them a top choice @ slightly over your budget $700 a pair.
The JBL 530 (and the 570 as well) is EASY to recommend for $250. While the Polk L200 and JBL 530 have some distinct differences I found I enjoyed them about equally with perhaps even a slight nod to the JBL's. Given the price differences and your budget the JBl is EASY to recommend.
By the way the Polk L200 has a pretty narrow dispersion in very top end and I really like that, I completely see the value in such a design and love being able to use the toe to really dial in the high highs.
The 570's are solid if floor standers work. Very dynamic for the price and I value dynamics a lot.
I appreciated but did not fall in love with the KEF Q150, little bro to your Q350 option. Something about the upper treble is just not right for me, I understand the jury is out on material sound but man does that tweeter sound metallic (and I often like metal dome tweets).
Still I can see what folks like so much about KEF in general.
I have never heard the UB52 2.0 but have heard the original. It was an okay sound to me that never gets exciting and always sounded a little to "fancy and a bit soft", works great for some material and yet for anything with drive and rock and soul - the ELAC just didn't have it.
PS Philharmonic Ceramic Mini is coming soon, slight OB but $700 is close. Dennis Murphy design.
https://www.philharmonicaudio.com/