FCM isn't working and doesn't allow to Add Platform properly

I can’t Add a platform if I have added the FCM native plugin, because of the problem Ionic has with GoogleService-Info.plist file. When adding an iOS platform, this file isn’t correctly copied into the Platform directory, so the “add platform command” finishes with an error and doesn’t add all the plugins in config.xml.

If I add FCM after adding the iOS platform, then I can’t build it. This is a vicious circle, with a fundamental problem in either the way Ionic adds a platform or with the native FCM plugin.

Has anyone encountered this error before? Any advice on how to go about it?