So this is challenging...you are looking at trying to get an analog/neutral sound which only is relevant within the context of your system. Looking at the two other components that you have (PrimaLuna and Harbeth), I would expect your system to be neutral to a hair warm which means if you go with too warm of a DAC, you are likely to end up with the system sounding dark or laid back. I would look neutral to a hair bright and you end up with a natural and engaging sound.
I would look at:
- Bricasti M3 (or M1 used) as these are dead neutral. Soundstage is huge and they are detailed and engaging. Incredibly musical and fun to listen too
- Rockna Wavedream Edition SE. Your amp is single ended. The Rockna is incredibly detailed. The soundstage is massive and it is one of the most neutral units I have ever heard. Part of the challenge in describing it is that the sound doesn't stand out in any way.
- Audiobyte HydraVox - it is similar to the Edition SE in sound but is FPGA rather than R2R. It is wonderful sounding and with the HUB (which is hard to get) it is really great sounding and Roon ready. The challenge is that when the DAC changes tracks it makes a clicking sound.
- On the brighter side, the Weiss 501/502 will be in that price range used. It is definitely forward vs neutral but with the very musical system you have could land you in a good place.
- Chord TT2 is a great DAC. It is brighter and will lack the scale of the Weiss or the Rockna in terms of soundstage width and height but has incredible depth and stability. No one is better than chord between the speakers.
I know this is unhelpful as all it does is add to your list which is already incredibly long. Best thing to do is borrow a unit of two and see how it performs. You might try a neutral unit and a brighter unit to see how you enjoy them with your system.
The only way you can tell is to try one in your system.
Full disclosure, I am a retailer for all of these brands. I have tested lots of DACs but have never heard the Terminator or Holo May and can't speak how they will compare.