I have iTunes Match, but 1) it isn't free, 2) it doesn't seem to do what I want - and often mis-matches, and 3) it doesn't seem to play well with Apple Music so

I have iTunes Match, but 1) it isn't free, 2) it doesn't seem to do what I want - and often mis-matches, and 3) it doesn't seem to play well with Apple Music songs. There doesn't seem to be an easy way to maintain a hybrid library that includes your (owned/library) songs as well as Apple Music (rented/streamed) songs and lets them coexist peacefully and easily sync and stream across devices. I don't understand the part about why my suggestion wouldn't be a better system for cloud syncing and streaming a local Music (formerly iTunes) library, if you have one, across devices, which is the original context of this discussion. It would seem to solve the OP and PP issues. Pure streaming is clearly a different use case, as users only need to sync playlists and metadata and won't run into those problems in the first place. The part I do understand is that Apple doesn't seem to care as much about local music libraries anymore, probably because they don't create recurring subscription revenue. And because Steve Jobs turned out to be wrong about people wanting to own rather than rent/stream music and video: renting/streaming is just too darned convenient, and manual curation is such a pain that most people don't want to deal with it - while automatic curation is buggy and often doesn't do what you want.