@oday In my case, it's like the one you describe that I have experience developing with Android with Java. Now I'm learning Kotlin, using this reference (
https://superkotlin.com/resources-learn-kotlin/) where you put examples in java and how they would be in kotlin, to give me an idea. Then in Android Studio, when I start projects already done, I have created another branch and I am doing the conversions automatically little by little and focusing on the changes.