all digital art is not copyrightable as it was created with software that did most of the work

This is a really weird idea of what making digital art actually involves. Drawing on a screen with a stylus isn’t somehow not art made by a person because it’s digital instead of on paper. Even if you use a mouse to make pixel art or modify 3D models, that’s still human artistic decision making involved. Non-AI digital artwork doesn’t involve just pressing a button and getting art.