Will there be Google Sheets API v4 support for Dart/Flutter, if yes when is it coming? It already has support for many languages but Dart/Flutter is not listed in their guid
There's a dart 3rd party library that helps to perform basic operations https://pub.dev/packages/gsheets.
You can also use official library https://pub.dartlang.org/packages/googleapis that helps to perform almost any operation, but it's more difficult to use and sometimes requires knowledge of the API https://developers.google.com/sheets/api/reference/rest