Fyne Audio F502 or Sonus Faber Sonetto V

If your dealer has a pair of the Opticon 8 mk2 you should test those out at home, and also the Sonetto V.  The Sonetto may have more "detail" but it's really just peaky and fatiguing top end (Olympica Nova line doesn't have this problem).  The Opticon 6 mk2 is dollar for dollar the best speaker in that price range on the market in our opinion, but if you're comparing to Sonetto V, you should be fair and jump to the Opticon 8 or Rubicon 6.

As far as low level listening goes, yes, unless you can pull the Oberon 7 way out from the wall to get rid of any room gain boundary effects, they will be very warm sounding which wont translate well to low level listening.  

If these Joseph Audio speakers are still available they’d give you what you’re looking for and save you some good $$$.  They completely disappear and throw off a deeeep 3D soundstage like few other speakers, and they have lots of detail/air but present it in a very natural way.  Definitely worth a look IMHO given what you’re looking for, but if they don’t work out you can turn around and sell them for little/no loss so very low risk. Best of luck. 
https://www.usaudiomart.com/details/650003701-joseph-audio-speakers-rm22xl/