DAC for Aurender N200

For past 2 years I have been running Aurender N200 into Musical Fidelity M6s DAC. The DAC is built like a tank and very versatile, but I must connect via coax since Aurender clock is superior to DAC clock.
Well, I am ready to upgrade DAC for SQ reasons and presently inclining to PSAudio MkII for US mfr, good reviews, good service, current bargain price.
Q1: What DAC (<$8k) would you consider an optimal match for the N200?
Q2: N200 has very few outputs compared with other streamers in its price class.
I know Aurender has always inclined to USB. All else being equal, is USB the best output?