>But maybe creativity exists precisely within boundaries, because they define the space in which our ideas can play with one another.

This, so much: boundaries are the origin of creativity!

If I say "fill this blank page with something", the least creative person in the world can do so. But if I say "fill it with a picture of a crow fighting a snail" or "fill it with an essay justifying the right to free speech", that is when the creativity will come out.

This is why I find it so frustrating when TV/movie writers for established franchises feel the need to get "creative" and completely change their work from the original. No, you are not "creative" for making something that doesn't play by the (meta-)rules of that show/universe! (Star Trek Discovery, I'm looking at you.)

To the contrary, you lacked the creativity to make fun new material to watch ... while staying within the boundaries of what made people like the show/movie in the first place.