With $15k for a streamer + DAC you are in what I call the "Pride of Ownership" price range. The sound quality of digital gear has become more similar as companies refine their products in the face of stiff competition. Whatevery you buy will sound wonderful.
Hifi Rose makes a gorgeous streamer (RS130) for about $5500 that has about every feature you can imagine and it’s built like the proverbial brick.....house. That would leave a lot of money for a DAC. I can second the recommendation of a Tubadour IV which costs about $3500. I have one and have compared it to several more expensive DACs and it definitely holds its own. I would have trouble justifying spending more than this on a DAC unless you need a feature like HDCD decoding.
If you could think of something else you might do with $13,000 you could get an Eversolo Dmp-a8 for $2k which will do it all. This unit has received gaga reviews and I suspect the SQ difference between a $15k streamer/DAC combo and the Dmp-a8 would be disturbingly small. A conservative strategy would be to get the Eversolo and use it for a while. Then if you have an itch for an expensive DAC you could just use the streamer function of the Dmp-a8 and hook up the DAC to it. This would give you the ability to compare the new DAC with the one that is built-in to the Eversolo so you can see if you are getting better sound.