DAC Suggestions

I’m in the market for a new stand alone DAC upgrade from my current Border Patrol which is fed by my Innuos Zenith Mark III server.. My budget is $3K - $6K new  only & like the natural, minimally “ digital” sound of my existing one but would like some more detail, a bit tighter bass & better imaging while not sounding fatiguing like many high end systems I’ve heard. Some reviewers suggest that a non over sampling DAC is usually the best way to achieve this, what do you folks think? 

Does such a unit in this price range exist in anyone’s experience? 
 

Thanks for your help.