AFTERLIGHT: The Apartment

The developers describe how their game uses AI generated content like this:

Some visual assets and textures used in this game were created or assisted by generative AI and have been reviewed and modified by the developer before being included in the final game.

Required on Steam store pages since 2024. It covers content that ships in the game, on its store page or in its marketing — Valve does not require a disclosure for AI tools used during development, so this says nothing either way about how the game was made. Check it on Steam.