Add External DAC or Upgrade to a New Streamer / DAC?

I had the rs250 streamer/dac for almost a year and decided to add Gustard R26 external  dac.  The soundstage and clarity is obvious and  noticable . I can listen my music at lower volume with the R26 with better sound quality.  I sold the rs 250 for trying Roon with smallgreencomputer combo on the r26.  I don't accept the fact the hifi rose don't want to develop Tidal connect and they stick with their buggy software.  Even the free bubleUpnP is better than rose connect.  

I am not a roon fan  and Now I am waiting my eversolo dmp a6 streamer to join my R26 by using Tidal connect with I really like the AI for track radio and discover new artists. The nice thing about rs250 is its hdmi output, internal drive bay for music storage and vumeters.  You can have the same for half money with the eversolo streamer.

So yes, adding and external dac above 1.5k$ (r26, a26, pontus 2, etc...) to your rs250 will bring you to another level.

I'd like to thank everyone for their contributions to this discussion. I've learned a lot and have gotten some very useful information to work with moving forward - it's appreciated. 

If you want great sound at a reasonable cost get a MHDT Orchid DAc with a 6922 tube adapter and a used Logitech Touch.  Probably under $1700 and sounds wonderful using Pandora.  This combo was better than the other streaming services available in testing, not just someone told me.

With USB connection DAC uses its own free running clock and requests data from streamer when it needs a new portion. USB connection is asynchronous and does not carry any clock information - only request from receiver (DAC) and response from sender (streamer). In that case jitter is only limited by the quality of DAC internal clock.

Other type of connections are synchronous and thus all devices should be slaves of the same clock source. This can be DAC internal clock (propagated to streamer), or DAC  is also a slave to some external clock source. But in that latter case jitter is limited by the quality of DAC circuit that synchronizes local clock with external master.

If clock distribution is not possible, then ASRC in DAC is the only way to minimize jitter, but ASRC may add its own distortion.

I too am considering either a HiFi Rose or an Eversolo, but only for the streamer portion. I would use an external DAC with either of these boxes.

I had a borrowed RS250 inhouse for a few weeks and loved some things about its GUI, especially the HDMI out, which lets you stream YouTube or display the streamer’s menus on a TV. Given that my "serious" stereo system also supports the front speakers of a multichannel home theater, that functionality is pretty handy.  And unlike some DACs's HDMI ARC implementations, it transmits video to a TV, not just audio.

Has anybody had the chance to compare the two interfaces in depth? Enough of a difference to warrant a multi-kilobuck price difference?