From a Google Blog Post
We’re grateful to the dedicated Stadia players that have been with us from the start. We will be refunding all Stadia hardware purchases made through the Google Store, and all game and add-on content purchases made through the Stadia store. Players will continue to have access to their games library and play through January 18, 2023 so they can complete final play sessions. We expect to have the majority of refunds completed by mid-January, 2023. We have more details for players on this process on our Help Center.