This issue is a common headache when working with React Native flavors and connecting a physical device to the Metro bundler. Let me share a possible solution that can help you resolve it. Since you have already tried adb reverse and clearing the caches, let’s focus on a couple of other steps that might have been overlooked.

Possible Causes and Fixes

1. Bundle Mismatch for the Flavor
   The index.android.bundle might not be correctly associated with your flavor. Ensure you have not accidentally created a production-style build for your custom flavors. Check your gradle.properties or build commands to ensure debuggableVariants includes the correct variant (localDebug).

   • Add this in your build.gradle:

     debuggable true
     applicationVariants.all { variant ->
         if (variant.buildType.name == "debug" && variant.flavorName == "local") {
             variant.outputs.all {
                 outputFileName = "index.android.bundle"
             }
         }
     }
     

2. Ensure Flavors Are Passed Correctly to Metro
   Metro bundler might not know which flavor is being used. Try explicitly specifying the flavor and mode when starting Metro.

   Modify your package.json to add:

   "start:local": "react-native start --reset-cache"
   

   Then, run Metro before installing the app:

   npm run start:local
   

3. React Native Flavors Configuration
   Double-check your settings.gradle and build.gradle files. Ensure that your localDebug flavor is correctly mapped and resolves to the right build variant. Sometimes, mismatched flavor names can cause issues.

4. Device Connectivity
   Run the following commands again to ensure proper connection:

   adb reverse tcp:8081 tcp:8081
   adb shell input keyevent 82 # Ensures the device stays awake
   

   Also, check the ipconfig or ifconfig on your system and confirm that Metro is serving on the expected IP address (default is localhost:8081).

5. Enable Cleartext Traffic for Debug Flavors
   Add this to your AndroidManifest.xml for the localDebug flavor:

   <application android:usesCleartextTraffic="true" />
   

6. Check App Installation Path
   Sometimes flavors generate different application IDs that do not match what the Metro bundler expects. Verify that your com.noteninja.debug is correctly being resolved.

7. Run Metro with Specific Configurations
   Sometimes, Metro bundler needs explicit instructions. Run Metro like this:

   npx react-native start --reset-cache --port 8081
   

8. Rebuild Gradle
   If none of the above works, try a full rebuild:

   cd android
   ./gradlew clean
   cd ..
   npm run android:local
   

Additional Debugging

• Ensure the device is connected properly by checking adb devices.
• Use adb logcat to check logs for more specific errors.
• Open localhost:8081/debugger-ui on your browser and ensure Metro is running.

By following these steps, you should be able to resolve the issue. If the problem persists, try sharing the full logs for deeper analysis.