[Help, Firebase Crashlytics] Unreadable firebase crashlytics after obfuscation

[kkoken]

Hi everybody, I have been a struggle with the unreadable firebase crashlytic report for quite some time.
I have already asked my question on stackoverflow, but I have no response.

Since we obfuscated our code on the Android side, we cannot get readable reports.
I have mentioned two* methods to get readable on stackoverflow. However, I have not reached success.

Additionally to StackOverflow, I have added to proguard : android.enableR8.fullMode=true & updated

  buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
            signingConfig signingConfigs.release
            // -------------------------------- These lines are added   --------------------------------
            firebaseCrashlytics {
                mappingFileUploadEnabled true
                nativeSymbolUploadEnabled true
                unstrippedNativeLibsDir "build/app/intermediates/merged_native_libs/release/out/lib"
            }
            ndk {
                debugSymbolLevel 'FULL'
            }
            // -------------------------------- These lines are added   --------------------------------
        }
    }

My general config:

pubspec

flutter: 2.10.0
dart: 2.16.0
firebase_core: ^1.4.0
firebase_crashlytics: ^2.4.5
classpath 'com.google.firebase:firebase-crashlytics-gradle:2.8.1'
classpath 'com.android.tools.build:gradle:7.0.4'
kotlin_version = '1.6.0

proguard

-keep class androidx.lifecycle.** { *; }

-keepclassmembers class * extends java.lang.Enum {
    <fields>;
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keepattributes *Annotation*
-keepattributes SourceFile,LineNumberTable        # Keep file names and line numbers.
-keep public class * extends java.lang.Exception  # Optional: Keep custom exceptions.

gradle.properties

org.gradle.jvmargs=-Xmx1536M
android.enableR8=true
android.useAndroidX=true
android.enableJetifier=true

  buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
            signingConfig signingConfigs.release
            firebaseCrashlytics {
                mappingFileUploadEnabled true
            }
        }
    }