nice work so far, gl in the future with it.
For non-copyright music, possibly look in to older / classical music? I think that lots of the real old stuff would have been made before copyrights really came out (similar to real old movies which can be shown wherever / used in research projects because they were made before copyright really got in to the business).
Also for those saying that they feel bad they aren't as good, idk why. If you really want to get better at this game you just have to willfully try during games and after to realize how you better yourself and work at it. It's the same as anything else you do. If someone else puts more energy in to getting better than you, can better see their mistakes and shortcomings, and/or just want it more, they will do better.