I suspect you are compiling using the command line. While it’s viable, it’s probably not a good option to do so. When using Gradle and the Kotlin/Native plugin (or Kotlin/Multiplatform with a native target) each compilation step is carefully cached and only some portion of your code will be recompiled only if necessary.
Using gradle does not mean you won’t use the command line! I often use Gradle from command line, the same way you would use a Makefile!
Also keep in mind that K/N is in beta and K/JVM received a big boost in copilation speed just recently and its development it’s much ahead oh K/N. Give it some time