https://creativecommons.org/2023/03/23/the-complex-world-of-style-copyright-and-generative-ai/
Copyright historically has not covered style until recent legal action. The Marvin Gaye Estate vs. Pharell Willians and Robin Thicke (Marvin Gaye estate vs Robin Thicke and … – Lost In Music). That case establishes that something that sounded like what the plaintiff would have done is subject to copyright and therefore must be licensed. It is a terrible decision for music, but it covers the case this CC article dismisses. What the article really is suggesting is that artists need to trademark their style. Getting that working properly is going to take a bit of time and effort, but it fits better. Much like software patents not being a good fit, it is where the legal structure took us.
Most importantly, for generative AI, asking for something in the style of someone is clearly copyright infringement based on the legal decision. Who should be on the hook for that is to be determined (user or the generative AI provider).