I will be greatly surprised if they give you a detailed list of all the differences. Somebody will have to spend time with two enormous databases with millions of tracks and it is quite possible they have completely different departments for the different country stores. Then, of course, you have to sit down and review the lists yourself. If you're worried about a particular artist then just check the Chinese list. Or just pay the couple of Euros a subscription would cost for a month and see if you're happy with it. It kind of strikes me you're really being fussy over something with much, much easier solutions and with a lot less time investment (I alone have invested 20 minutes of my time on this thread).
You do know, of course, that Apple Music includes Match which means if you have a copy of certain music on your computer it will be placed in iCloud for your access there too?