For New:
Check out the AVM Ovation A6.2ME. AVM works very well with speakers that are a bit forward like Focal or Magico and have relatively low impedance and are hard to drive. It lists for $8K so I am pretty certain you will be able to get it on your budget.
The Naim Supernait will pair well with them. Naim and Focal go together like peanut butter and jelly. The Supernait lists for $4990
Musical Fidelity NuVista 600 or 800. The 800 was just discontinued but is not being discounted. The 600 lists for $7290.
These will all deliver tons of detail without a fatiguing sound as they are on the neutral to warm side of the audio spectra.
For used:
If you can find a Gryphon Diabolo 300, it is an insanely good match. As you can see, multiple people have it.
A Mark Levinson 585 or 585.5 should be in this range and will be a very good option.
You could also see if you can find something from Accuphase, Boulder or Constellation used in this range.
Full disclosure...I am an AVM, Naim and Musical Fidelity dealer. I have no affiliation with Gryphon, Levinson, Accuphase, Boulder or Constallation