Recommendation for Dac for streamer

Given that you have an ACS10, the D-03x seems pretty redundant.  You don't need a disc transport and although Luxman doesn't make a bad DAC, it's not like they have this sterling reputation for making incredible DACs. 

I would buy a separate DAC.  Given the quality of your gear, I might look a bit higher end.  Not sure what your budget is.  

In the $4500 - $6500 range, Audibyte HydraVox, Rockna Wavelight, Chord TT2, Bricasti M3, Holo May are all excellent but different.  Depending on if you prioritize soundstage and image vs detail retrieval and then if you want something brighter vs more neutral dictates the choice.  

At the next level up ($9K-$12K); Rockna Wavedream, Chord Dave, Bricasti M1, Weiss 501/502, MSB Discrete - there is very little compromise.  it is just how warm, neutral or bright you would like your sound profile to be.   

Based on your description, I would be inclined to think the following three DACs would be brilliant for you:

Rockna Wavelight - This is an R2R DAC with an FPGA interface.  It delivers a massive and very engaging soundstage with a slight emphasis on bass which delivers warmth.  It is not the be-all-end-all in terms of detail but it is very good and one of my favorite products in the $5K range.  It lists for $4950

Weiss 501/502 - This is a delta sigma with significant processing capabilities including room correction and analog mode.  This has a warm musical quality to it that is just to die for.  It is everything the Wavelight is with reference level detail.  This will go toe-to-toe with a Chord Dave or dCS Bartok in terms of detail.   It lists for $9k/$10 depending on whether you want/need a balanced headphone amp.  

MSB Discrete - This is a pure R2R and entry level DAC to one of the best DAC maker's in the world.  They have an amazing trade-up program if you think your journey will continue to higher end DACs that makes this a very appealing option.  MSB has a warm musicality to it that is second to none.  I believe the MSRP is in the $11K range and options can push the price higher as it is highly customizable.  

Reviews are available on all of these items.  Do a little research and it will boost your confidence.  Full disclosure, I am a Rockna and Weiss dealer.  I have no affiliation with MSB other than we have several very happy customers in common.