The art for yourself and for other people
The basic premise of this differentiation though is that there is a clear separation between yourself and others. Once we start believing in a mindset where there is no "separation of self" (non-duality, oneness, buddhism etc.), then serving yourself and the greater good will become the same thing. What makes you happy will be something which makes others happy. And then both approaches are right at the same time.
“But, when you are doing something for someone else, you are also selfless. Your motivation is not about you but other people. That could make it easier to get into the flow state where you don't feel your own ego's strong sense. And that's when you're creative and alive the most.“ - When you do something for someone else, isn't that because you care about their opinion of you or how you will be perceived by others? Is there even such a thing as a truly selfless act?