Perhaps Steam has restrictions related to the use of artificial intelligence. Recently, a redditor under the nickname potterharry97 complained that his game was not allowed on the site due to the presence of AI-generated assets.
According to the developer, Valve demanded to prove that he owns the rights to all the content on which the AI he used was trained. The redditor did not have such rights, so he manually modified the assets so that they did not look like the AI created, and then submitted the game for verification once again. However, he was again refused.
potterharry97 added that he had been waiting for the Steam moderation decision for more than a week. All his previous games were checked in one or two days.