"AI-generated" works can be copyrighted. However, on the condition that the AI-generated elements are explicitly mentioned in the "Excluded Material" field. In other words, the parts generated by AI are not protected, only the parts that are expressed by human creativity. Courts in the U.S have already rejected registration for many AI works because of that. Regardless, it's still a contentious matter.

P.S. I am completely opposed to (generative) AI as well as the copyright system. I'm just stating my findings researching the law and court cases.

As mentioned elsewhere in this thread it won't matter either way unless tested in court and that will never happen for most companies.