HQPlayer

[Confused]

Yes, I'm still using HQPlayer (via Roon) and my system is very similar to yours. I find upsampling everything to DSD256 to sound the best (the max the MC3+USB can receive) but I will have to figure out how I can programme the MC3+USB to convert this back to 192kHz.
I also found that setting the max bit depth at 24, rather than 32 may sound better too. A bit perhaps (pun intended)
Finally, a knowledgeable friend suggested turning off the MQA decoding and rendering in HQPlayer (that is in the DSP setting options in Roon) and just turn on the "Enable MQA core decoder" in Roon.
What settings do you have?

Hello Mr Z

A long time ago I experimented with feeding DSD to the MC3+USB, but found that I preferred the sound keeping with PCM.

For a while now I have been using poly-sinc-short-mp, NS9, upsampling everything to 24/192.

I am sure you are aware that there have been a number of new filters added to HQPlayer in recent updates.  I have not yet got around trying these.  My most recent "upgrade" has been the use of convolution filters produced using Focus Fidelity Filter Designer.  This has made a pretty profound change to how my system sounds (in a good way), so I need to get fully used to this before I try the new HQPlayer filters.