API Key not found when adding Google Maps to Flutter
If you place the <meta-data> tag in the wrong location at first, lets say in the <activity> tag.
You need to run "flutter clean" which cleans up the android and ios build directories.
Then ensure you create the
<meta-data>tag right above the</application>tag.
You should be good to go. I ran into this issue and it worked for me. Found the answer on github issues.
You've currently got the meta-data element as part of the activity. The documentation says to make it a child of the application:
In AndroidManifest.xml, add the following element as a child of the
<application>element, by inserting it just before the closing</application>tag
So I suggest you try moving it to just after </activity>.