Maybe you should take a look at the RPG course on GameDev.tv. Some of the content might be interesting for you.
If you search for “James Doyle” or “Pete Jepson” on Udemy, you will also find good courses that teach valuable gameplay mechanics. It does not always have to be GameDev.tv.
The tip I can give you about music is this:
When I am not sure whether a certain piece of music fits my scene, I put on headphones, open YouTube, and search for music that I think might fit. Then I start the game in Unity Play Mode, preferably in fullscreen, walk around the scene a bit if necessary, and let the music affect the scene.
You usually notice very quickly whether the music fits or not. I do the same with sound effects: just try them out and let them work in the scene.
If you want to learn more about these kinds of things, I can only recommend joining the GameDev.tv Discord and asking there. After the rating period ends, there probably will not be much activity here anymore.