Textual inversion involves providing self-created images, which should confer copyright in the same way AI images of DC's superman are considered to fall under

Textual inversion involves providing self-created images, which should confer copyright in the same way AI images of DC's superman are considered to fall under the copyright of DC. In other words, commissioning fanart still allows the original owner of the IP to exert copyright -- shouldn't that be the case here?