I’m an old timer as well. Also, a big fan of Audio Research, for simply performance reasons. My main system is all Audio Research. You can see photos under my User ID. I use an Audio Research Reference CD9 SE as my DAC. It is simply outstanding and actually performs against much more expensive DACs.
While you can use a PC. I would recommend getting a streamer. Even if it is a cheap budget Blue Sound to start with. It will sound better than a PC and avoid the conversion from USB to coax. This will let you get familiar with the world of streaming.
In todays world streaming can easily provide the same or better sound quality as a CD or vinyl. In my system CD redbook = stored files = streaming (better if higher resolution) = vinyl in sound quality. To get all the way there you will need a very high quality streamer. Like a good Aurender. My rule of thumb is to match the investment level of each component to get the most out of your system. So, phonostage = preamp = amp = DAC = Streamer... roughly. You have to do the research to get the best of class of each. I just say this for longer term thinking.
The service to get is Qobuz. For $14 / month you get access to over 10 million albums with over half a million that are high resolution. This is a game changer and fantastic for us retired folks that have time to explore the world of music and really enjoy it.
Feel free to send me a private message if you want to talk off line. George