How to approach streaming will depend on your personality. For me, wading into the shallow end is a great way to either become frustrated or to spend a tremendous amount of money constantly upgrading until I get something at or better than analog..
You want a separate DAC box and Streamer box.
I have / do own streamers / DACs from $200 to $20K. In general they get much better sounding the more you spend. To get high end sound quality $5K is the general area for both the streamer and DAC can get you there. Improvements continue the more you pay… in particular the streamer makes incrementally larger differences in sound quality.
I highly recommend the best Aurrender you can afford, even their entry level is phenomenal, although Lumin are also good. Qobuz is the best service with the most high resolution albums.