I cannot show the google maps on iOS when I used the flutter to development.
I don't know why it cannot show it, but can show marker icon....
the function can running in Android, but cannot running in iOS
Your API key must persist the properties for using the iOS platform.
So, enabling Maps SDK for iOS platform should work.
Also, check your installed XCode and target sdk version: it must be higher that 12.0
Here is the documentation link