Well now youve gone and done it!
Single or multi box solution.
As I saw recently posted here on another thread as an answer Yes.
Multi box = multi stuff. Basically more wires and shelf spaces are needed.
Single box? Well you have just opened the door a crack now, as you already have two of those.
Id say DAC as well, despite the addition of more wires and space usage.
If so then, one with great jitter elimination and several common interfaces. And Id use it with my most revelatory CDP on hand.
A tube DAC might not be necessary too to gain you that fluffier presentation. Deleting a load of jitter will aid you towards that promise.
Id address warming or filtering things downstream and NOT with the source. Ever.
Lavry DA10 was a very musical DAC and not too too expensive as DACs go. Im sure if you check out the archived threads here on such a subject youll gain more choices.