AI isn't a legal entity that can do anything, let alone hold a copyright. It is an inanimate box of numbers.
The only two things that can transact with any legal system in any way are humans and groups of humans.
That should be obvious but unfortunately lots of people believe (or have a vested interest in pretending to believe) LLMs are living, thinking, sentient entities and that belief is going to influence the politics and legislation around AI to some unknown degree.
But a human can hold the copyright on the output of an AI - but the requirements for that are not clear in the US yet. They are clear in the UK but the government is thinking of changing the law.