Please note that in addition to channel load, the stability and speed of your internet connection, the speed of game/updates installation also depends on which drive the game/update is being installed. The installation process on an SSD is much faster than on an HDD.
If you do not minimize the Game Center during the installation of a game/update and keep it in the foreground, the installation time will also speed up.
If you see the warning "Waiting for game distribution availability" for more than two minutes when trying to download a game, please refer to this article.
If you encounter problems when installing a game downloaded via the Game Center or when installing updates (patches) for such a game, please create a request on this topic, providing a detailed description of the situation. Be sure to include the name of the game, the antivirus or firewall installed on your computer, and any errors that appear during the installation process. If necessary, attach a screenshot. Include diagnostic data with your request.
How to create a request is explained in this article.