But in general it's just the same Java, e.g. you would search for "how to do that in Java", not "in Kotlin".
While Kotlin closures, receiver arguments, "it", extension functions, nullability operator, var/val, "when" pattern matching, sealed classes and smartcasts are mostly implemented as syntactic sugar, combining all of the above enables some interesting programming patterns. Some examples are Compose for building reactive/functional UI and TornadoFX for declarative UI on top of JavaFX.
Coroutines and suspend functions provide structured concurrency and an async paradigm that interopts well with the "old" Java CompletableFuture apis and existing libraries.
Kotlin Flow is the answer for observability and rx-like reactive programming.
Kotlin multiplatform (while still in early development) allows sharing code between JVM, web and native targets (even iOS) with a decent-ish build system.
I'm very bullish on the future of Kotlin and have been using it for years as my goto language for backend apis, MPA's, Android and JVM desktop projects. I'm excited to expand that into some combined web/iOS/android/desktop projects in the very near future.