A while ago, I tried compiling a simple Kotlin hello world on the command line (my preferred "IDE"). I vividly recall it taking around 7 seconds to even compile, every time. It could be that my rickety laptop was to blame, but not probably wholly.

AFAICT, the only viable avenue of Kotlin developemnt is by using an IDE (or maybe launch a Gradle deamon--but that'll be another rant).