I must second the MSB recommendation. I have the Analog Dac with the upgraded power supply (Analog Power Base). Extremely smooth, great detail, separation, wide and deep soundstage, luxurious sound. You said you are OK with buying used and this dac can be found used for 6-7k USD, so well within your budget. Also, @tvad 's suggestion to buy used and try several dacs in your own system is spot on in my opinion.
@jjss49 has generously shared his very extensive experience with dacs in a recent thread, worth reading if you haven't already done so. MSB Analog Dac is among his top 3 preferred dacs iirc.