What Anthem units are streaming DACs? As far as I am aware, there is only one product on the market that is a streaming DAC with room correction that ISN'T also an integrated amp, and that's the NAD C-658 you already mentioned. If you look at using an integrated amp, you get some additional possibilities. All of these have pre-outs for external amplification, if you don't want to use the in-built amps:
NAD M10
NAD M33
Lyngdorf TDAI-3400 (over budget but can be had under $5k used)
Arcam SA-30
Micromega M100 / M150
You could potentially count Devialet too with SAM, but that is speaker specific so you have to own a pair of speakers they have a profile built for.
If you drop room correction from the list, more options open up (ELAC DDP-2, for example).
NAD M10
NAD M33
Lyngdorf TDAI-3400 (over budget but can be had under $5k used)
Arcam SA-30
Micromega M100 / M150
You could potentially count Devialet too with SAM, but that is speaker specific so you have to own a pair of speakers they have a profile built for.
If you drop room correction from the list, more options open up (ELAC DDP-2, for example).