I'm not clear on what the status of the piece is after the ruling. As in, let's say I got AI to generate a cartoon character preparatory sketch in black penlin

I'm not clear on what the status of the piece is after the ruling. As in, let's say I got AI to generate a cartoon character preparatory sketch in black penline. If I printed that out and used it as a reference to do a "clean room implementation" of the character — do I now own the copyright, since I'm the first person to produce a copyright-eligible rendition of that likeness? Or since it's a copy of an uncopyrightable work is the character immediately in the public domain, as if it was generated by a human & then given a really permissive license?