They are very close. The biggest issue with Kotlin is that it has to keep up with Java language changes. It used to be a "strictly better Java", promising zero-friction migrations, but whenever Java adds a new language feature Kotlin has to accommodate it or it will no longer be able to "inherit all of the JVM ecosystem".

It's the same with F#. F# used to be ahead of C#, but now every time there's a new C# language feature it's F# that has to adjust or deal with friction in some other way. Discriminated unions are the next big thing that will require F# to put up with C#.