I feel like creative motivation for a 4 may be more focused on expression of something inside themselves in an effort to find significance for themselves, but a sx 6's creative motivation may be more based on a desire to attain connection with others. In this way, a 4's motivation for creativity is more inward focused, whereas a sx 6's motivation for creativity is more outward focused.
A case in point: I publicly read something that I wrote a poetry reading a week ago, and I got to hear someone else read poetry who I surmise is either 4w5 or 5w4...so I think there was a 4 in there some where Anyway, I realize now that my words were comparatively more unifying and based on common ground amongst the listeners, whereas the other person's poem was relatively divisive, haunting, and yet maybe truly brilliant...like maybe only a 4 can write.
Relatedly, I wonder if sx 6's are more likely to create art that is short-lived and connects the artist to a large energetic audience (Eddie Vedder in concert comes to mind) than say sculpt stones that may have less likelihood to bring together lots of energetic people at the same time. I wonder if the sculpture art is more often chosen by 4's that want to create something that will last and show some kind of historical significance.