Question on up/oversampling and Assemblage DAC 2.6

[SashaV]

I am not DIY person, but considering the wealth of knowledge on this forum, I thought someone may chime in on the following question.
I had opportunity to hear Assemblage DAC 2.6 1704 in my system.
It was the first time I heard correct tonality of acoustic instruments, wealth of harmonics, long natural decays, never heard before details that are not forced upon you, and incredible pace and rhythm.
Although it had some serious deficiencies, such as problems with LF definition and confusion with complex music, where it would seem to generate tones of its own, overall it was the most pleasing digital piece of gear I heard.
Simple music (e.g. small orchestra) was just phenomenal.
I preferred it by a large margin over DACs in comparative price range such as MF X-DAC V3, Benchmark DAC-1, or players costing much more, such as for example Esoteric DV-50.
They all sound to me bleached out, out of pace. Technically they sound correct (e.g. go deeper, with better control, better S/N ratio), but utterly unnatural.
What was also interesting, Assemblage upsampler/de-jitter in front of Assemblage DAC destroyed what I found pleasing in its sound.
What is it that I like so much in Assemblage DAC?
Is it specific implementation of BB 1704?
Is it the lack of upsampling?
Are there DACs / players with digital input available on the market today that would be of a similar presentation?