Netcode for GameObjects (NGO) vs Mirror
Two of the most popular solutions for the underlying netcode of a Relay game include Netcode for GameObjects (NGO) and the Mirror Networking API.
The recommended best practice is to use NGO (in most cases) because it offers a stable breadth of mid-level features, such as network variables, scene management, remote procedure calls (RPCs), and messaging. However, the Mirror Networking API, with its simplicity and ease of use, is also an excellent choice for games that don't need the full set of features NGO provides.