@fleschler
Yes, you can get enjoyable sound from a streamer in the price range you suggest. A pre-owned Aurender, Auralic, Innuos would fit the bill.
But you have a beautiful, well thought out system and room. And, while you have a great collection of music, streaming via Qobuz or Tidal gives you access to an even greater library. With a streamer of similar quality to the rest of your system, you can explore that world library at the same quality as you enjoy via your CDs when played through your Poseidon. And, you’d have access to a large library of hi-res streaming content as well. Not all of it is good, but some of it is noticeably better than CD quality. With a good quality streamer, you might find you rarely spin a silver disk.
Dipping your toe in is a good start, but for your system, I’d jump in.
My two cents.
Best,