Maybe I'm getting cynical but in terms of longevity, I don't know how long JetBrains will be around and I'm not trusting Google to maintain a project for a long time. Can't believe I'm saying this but for perennial projects in that sphere, Java seems like the better option :/
Jetbrains is one of the best example of a bootstrapped company. They have a fantastic track record of 20+ years shipping and evolving some of the best IDEs out there
Same and with lots of Kotlin code in the wild on Android, I'm not too afraid to language will fade away. Bu in terms of active development like KMM; I don't like JetBrains being pretty much a single point of failure.