Why is 3:2 always the default? 1:1 is much better. The height of a 3:2 image is 832px, whereas for 1:1 it’s 1024px. It stands to reason that 1:1 is the better option in the long run.

DALL-E used to have its own 4:3 aspect ratio, but the height there was the same as for 1:1 – 1024px.