Aesthetix system – with or without a line stage?

I have been slowly building a stereo and HT system in my living room. I don’t have much experience with high-end audio, I used to have a modest surround AV system but now I am really into the great sounding stereo sound.

So far my “new” system is the following: Aesthetix Atlas Eclipse Power Amp and Aesthetix Romulus Standard CD/DAC. I also have an Anthem D2V which I use as a pre-amp for now. I stream the music from my NAS with a Lumin U1 mini, and my speakers are Martin Logan Montis’s.

As the Romulus Standard is not DSD compatible and my Atlas is an Eclipse version, I have decided to upgrade my Romulus DAC to Eclipse as well.

The question is, at the time of the upgrade shall I add an optional volume control to the Romulus and connect it directly to the Atlas, or would it be much better adding a Calypso line stage to this system?

There is a significant price difference between these 2 options. My dealer recommends the Calypso whenever I can afford it, and until that just use the Lumin’s digital volume control without any pre-amp. Obviously I don’t want to spend $1500 on a volume control if that is not a good solution, but with my limited experience and knowledge it is hard to understand the benefit of the additional line stage, as I don’t plan to add anymore analogue sources to my system…

Thanks in advance for the recommendations!