To cut the chase - in my experience, yes…the underlying character of an external dac is retained - if you are seasoned enough to pick up on the sonic characteristics of your dac. With XTC in the chain, the impact to the sound stage (clarity, etc), depending on your room’s setup, speaker type, etc, is unprecedented that a ’new’ listener can easily think the dac associated with the XTC is doing those things…its not. Its the processing algorithms and genius of Prof Choueiri and the Theoretica team.
IMO, the dac associated with the b4m and adio do what they need to do and team up well with the DSP, and depending on your personal tastes, could be all you want or need. You would need to entertain this yourself. The same hoopla applies here, this dac beat this mega dollar dac there, but does that actually apply to everyone’s personal taste? That said, BACCH built in the way that is presented by Theoretica is the most convenient and likely most elegant solution so far in terms of anyone else doing XTC. I hope to see other manufacturers enter the space in XTC.