Fellow boomer here as well. The advice of @arize84 is, in my experience, sound. When I needed to move into the streaming world, I went back to the dealer who had sold me my kit in the late 1990's, and he hooked me up. I am currently using a Linn Akurate System Hub to stream on my main system, and a Blue Sound Node 2i to stream on my secondary system. I use Roon on a Roon Nucleus media server to run both systems from my iPad and from my iPhone. I use the Qobuz subscription service to source my music. I am very happy with all of the above kit and services, which my dealer tailored to my particular needs, budget, existing kit, and tastes.
I hope your experience of streaming turns out to be as pleasant as mine has been.