My suggestion would be to complete the 2D course, try to make the projects your own after you finish it, get them to the public, ask for feedback and improve those games, that will give you the game design experience you’ll need because, at least to my knowledge, there are not many great game design courses out there, the courses in here do touch on that a little bit, but I think the real reason why there aren’t many great Game Design courses it’s because experience can teach you more than a course.
Participate in a few game jams, the Gamedev.tv team will be holding a game jam soon, @Brian_Trotter can correct me here.
I also suggest looking into other engines, Unity is great, it is my favorite engine by far, but using something like RPG Maker or even GameMaker can certainly make things easier, you can even start there and then move into Unity.
If you are looking for art courses, I suggest taking the following, you can find them on this site or Udemy.
There are a few other art courses I’ve taken, look for Jaysen Batchelor in Udemy, stick with his drawing courses because his pixel art course is not that good.