The case Community for Creative Non Violence Vs Reid (https://en.wikipedia.org/wiki/Community_for_Creative_Non-Vio...) solidifies a supreme court opinion that someone contracting a work and directing an author does not grant authorship to the commissioner of the work, it grants authorship to the person actually doing the work.
The author can grant authorship and copyright to the commissioner with a contract, but the monkey picture (and others) have solidified that only humans can be granted copyright. Since LLMs aren't human they can't hold copyright, and if the LLM doesn't have legal copyright then they don't have legal rights to assign copyright to you.