After decompile the apk BuildConfig.java file values are accessible

Question

I have created .env file in react native and from native side i'm able access the BuildConfig.KEY_NAME in MainApplication.java file But security team hS decompiled the app/APK using MobSF and can able to access the all keys from the BuildConfig.Java source file. How do we hide the values in BuildConfig file and how can we prevent accessing the BuildConfig.java file I have added proguard rules and minifyEnabled true.

  buildTypes {
    debug {
        signingConfig signingConfigs.debug
    }
    release {
        
        // see https://reactnative.dev/docs/signed-apk-android.
        signingConfig signingConfigs.release
        minifyEnabled enableProguardInReleaseBuilds
        proguardFiles getDefaultProguardFile("proguard-android.txt"), 
        "proguard-rules.pro"
    }
}

Did all the possible way But no luck yet. Could any body help me on this ?

My manager said don't use the NKD implementation using c/c++ approach Any help much appreciated