There's been conversation in #C0B8H786P around IDE/compiler performance.
People are reporting good results with 1.4-M1, but that may not be an option for a production system.
But from the #C0B8H786P channel, at a minimum, ensure you're using the latest IntelliJ, and try the 1.4-M1 Kotlin plugin in the IDE.
Take a read, and then you can make your own call.
And if you have any data to pass along, there is at least one JB person getting involved there to help solve this issue.