The best streamers are single function boxes made only to do this. They do not have variable output. The best is probably the Aurender W20SE… although I believe the W30 will be available soon. It is used nearly universally at audio shows for digital source. I can attest to equal Red Book CD quality on streaming the same resolution and better resolution on higher resolution. It equals my analog rig for sound quality… see my systems.
You want a separate DAC at the same or better quality. I can highly recommend the Berkeley Alpha Reference DAC. Altough I have a slight preference for my Audio Research Reference DAC CD9se. But exceptionally hard call. There are other exceptional DACs as well, but they can get pretty pricy.
In general combined Streamer / DACs will not sound as good as separates, all things being equal. So, I recommend separates.