How to adjust small gaps between colors?
It looks pretty good to me. You could make sharper corners by using smaller nozzle size. But beside of that there is not much you can do.
Keep in mind that you're attaching a cold plastic wall of one color to the hot plastic wall of another. There will be always a wall between those. It will never look perfectly even.
Hm? :o( But this is delaminated. It is printed like supportmaterial, which should not stick to the next layer.