I'm following the settings per Denafrips website using AISO.
https://www.denafrips.com/win-os
You can set upsampling to no limit, but I have mine capped at 32bit/384kHz. I don't know if it's the AISO plugin, the upsampling, or Audirvana doing some magic. But it somehow adds some "soul" into the music.
I never understood how people complain about the amp, especially the A90 bring lean, analytical, and lifeless. It's basically amplifying the signal you're feeding it. It's one of the most neutral reference amps I've heard.
For some reason I did not find the Burson 3XP to be a great match with Arya V2. It did have much better depth but the whole sound and image seemed off to me. I much prefer the A90D synergistically. The Soloist is a much better match with HEKV2 imo.