One issue in hi-fi audio is the surprising lack of good source material given the passage of time. For example - 20 years ago it feels like you could by a SACD

One issue in hi-fi audio is the surprising lack of good source material given the passage of time. For example - 20 years ago it feels like you could by a SACD with some classical music on it - and the quality was pretty darn impressive. I remember multi-channel audio in these. Despite 20 years of tech - when I try to stream or even buy some multi-channel audio for my HiFi rig it's basically super annoying as far as I can tell. No clear disclosure of actual channels / format etc. Am I missing something? SACD had 5,000+ titles out, you could just grab one and it worked. What's the current approach here for high quality multi-channel audio? My home setup is Klipsch 5.1 if that matters, but I'm happy if things play 3.1 if needed.