How to obfuscate cordova plugin java code

I have been working on ionic 3 mobile applications. I obfuscate typescript codes using ionic-voricles-obfuscate plugin (https://www.npmjs.com/package/ionic-voricles-obfuscate)

While reverse-engineering the APK using Apktool , Android library classes in cordova plugins are not obfuscated. The Application security team asking to Obfuscate the Java / Android packages using proguard in order to prevent the application from run time code manipulation , due to this my application is rejected by Appsec team. I have referred lots of articles , all are very brief introduction about proguard tool , I am very confused whether I am approaching the right method for obfuscating my Ionic mobile application. I am new to Mobile application development and don't have hands of experience in code obfuscation. Kind help needed from dev community for a quick fix. I appreciate your quick response , Thanks a ton in advance :)