Waiting so long for type safety and hoping it won't be a weird implementation.

Kotlin's implementation is very good, hoping with all my heart java will copy it

That's valid. Kotlins nullable types do help tremendously in that regard with AI-generated code. If Java nailed a nullable type system that's actually a win for Kotlin as well since Kotlin has to support "platform types" where it can't tell if Java code is producing null or non-null types.

That's probably the largest gap in usability.