"Это значит, что разработчикам многопользовательских игр на Unity нужно получать отдельную лицензию."
!==
"From a technical standpoint, this is what our clarification on our TOS means: if you want to run your Unity-based game-server, on your own servers, or a cloud provider that provides you instances to run your own server for your game, you are covered by our EULA. We will support you as long as the server is running on a Unity supported platform.

As an example, if you have made a Windows or Linux player build of your game to be an authoritative game server and run that on a server in-house, you can continue to develop, publish or operate your game as usual. If you rent a server or pay for a cloud instance to run the game, you can continue to develop, publish or operate your game as usual.

However, if a third party service wants to run the Unity Runtime in the cloud with their additional SDK, we consider this a platform. In these cases, we require the service to be an approved Unity platform partner. These partnerships enable broad and robust platform support so developers can be successful. We enter into these partnerships all the time. This kind of partnership is what we have continuously worked towards with Improbable."

связано больше со сторонними cloud платформами/sdk, чем с мультиплеером.
https://blogs.unity3d.com/2019/01/10/our-response-to-improbables-blog-post-and-why-you-can-keep-working-on-your-spatialos-game/