Hi
Some settings are server side, o365 or on-prem.
In example if you add a mailbox to an user in the admin tool or on o365, the settings is save for anywhere the user log on, but if the user use the "add mailbox" in the Email setting on the computer to make it appear, then it's a local settings.
For a group calendar usually it's a local settings client side if it's ticked or not to display by default, but it should be listed inside the calendar menu of the client or in OWA.