Hello,
In a Windows Server environment, Client Access Licenses (CALs) are typically required for users or devices that directly or indirectly interact with the server.
However, for your specific scenario using the server as a Dedicated Gaming Server, where users are connecting through a service like Steam, the requirement for CALs might depend on how the users are accessing the server and what roles or services on the Windows Server the users are utilizing.
If you are using roles like Remote Desktop Service(RDS) on the server, you will need to purchase RDS CALs in addition to the standard CALs. Each user and device that connects to a Remote Desktop Session host needs a client access license.
If the users are only connecting to the server through Steam to play games, and not using any other Windows Server roles or features, you might not need CALs for each person. Gaming is often handled differently than typical business server use cases.
You can consult directly with Microsoft product support for a definitive answer regarding licensing requirements.
Here's the contact information: https://support.microsoft.com or Global Customer Service phone numbers - Microsoft Support.
I hope this helps.
Best regards