For listening, it's either on Auxio on my phone (files on device over streaming), a few yt playlists that have some of my favorite songs (some downloaded, some not). That, or I have a few songs on NewPipe history that aren't saved anywhere else.
On my desktop, I use either Strawberry Music Player for my audio files and VLC for CDs (I have less than 10, but that's besides the point). Some of those CDs for some reason will just shut off after a few minutes into certain songs if I try to play it on the '92 Sony CDMan. I think it's just an issue with the CDs more than the CD player itself.
As for how I discover new music, it's usually from yt recommendations based on what I listen to, whatever catches my eyes. That or maybe it's music I find on OpenGameArt or maybe I'm looking up something like a certain vocaloid song on VocaDB or yt or on rare occasion NicoVideo and finding a cover of it or another song from the original producer.
Edit: Sony Discman, not CdMan