Kotlin/Native is LLVM based. Judging from the Rust experience compilation times won't ever be excellent. But Kotlin is multi-platform, so if you're not calling

Kotlin/Native is LLVM based. Judging from the Rust experience compilation times won't ever be excellent. But Kotlin is multi-platform, so if you're not calling into Java APIs then you could prototype suitable modules on the JVM where compile times are much better, then bring it to the native world later. Or use GraalVM native-image to AOT compile Kotlin/JVM to a standalone binary. That gets you same user-visible outcomes more or less, but you can then use all JVM libs, not just Kotlin libs.