dac for multiple sources

what should a person consider if they want to enjoy quality sound from an external dac and their sources are a cable box, dvd player, cdp, computer files via usb, and a sonos system? i've had a wavelength brick which is usb only and a proceed cdp which, prior to dying, handled a few but not the cable box. my budget is +/- $3k if bought used thru a'gon. my listening preference is more warm (tubes) than hard (ss).
The Bryston DAC would be pretty good for what you are looking for. I've owned the Wavelength Cosecant and I think this one sounds better.
Not sure of a DAC with FIVE digital inputs, but a Peachtree Nova MIGHT have enough.

No audiophile DAC that I know of will handle the DD output of a cable box unless one arranges for it to output S/PDIF and that, of course, as stereo only. Otherwise, the Bryston should do the job well.

Though your preference is warmth, given your requirements you might consider the Benchmark DAC1, in its various iterations. The DAC1 Pre, for example, I believe has 5 digital inputs, incl. USB and Toslink, and one analag stereo input (RCA). Pristine pure with great dynamics, one of the most widely reviewed and highly regarded dacs in recent memory. Check out the Benchmark Media website for multiple rave reviews.

Also has a great built-in headphone amp to handle up to 2 sets of phones and can be used as a standalone preamp too.

I have one and use it with multiple sources and it has been amazing.
Bryston, Benchmark, PS Audio Perfect Wave all come to mind.