Adding my voice to this as having the same problem and I want Apple to see that it may be a relatively large issue affecting many people. Nothing is more annoying than trying to work and then the iTunes icon bouncing because Cloud Music is down even though what I'm listening to is my own local library.
That said, over the years I've been fine with iTunes while complaints had been mounting against it. With the latest updates, I'm seriously considering an alternative player. I dislike the fact that I can't turn off the dumb Biography panel that appears when looking at my own music or the fact that if I'm scrolling through my collection of an artist and I decide to play a track, it plays but then a few seconds later, it scrolls automatically back to the top and then to top if off with the corruption of my music library.
I liked Spotify but not enough to pay for it and was leaning towards getting an Apple Music subscription after the trial was over but iTunes is the reason why I'm reconsidering.