No, Flutter also needs a Mac to develop iOS apps and Android SDK to develop android apps.
Gomatcha also requires Mac/XCode for iOS apps and Android SDK for android apps. I have been using Flutter to develop apps without Android Studio - just the flutter SDK + Android SDK + Gradle
hmm .. I am not sure I understand your requirement then.
Flutter implements its own widgets and has very little in common with the Android SDK.
I believe it is only used for its debug tools like adb.
What would be the point of getting rid of Android's sdk ?