Please don’t use Inception Forum for issues that are not related to the forum. Moved to Scripting Support.
You get this GDPR message when that UserId has played any to all of the games that are owned by you. You have to loop over all of these places and remove any data that you collected/saved in correspondence with that UserId. That also means external databases and analytics. You should know where you store user data since you are the developer of those games, so you know best where to look for data related to that UserId.