So transpiling to PHP
No, it would be very big project to do that.
It's one more backend for Kotlin.
Now Kotlin team works on compiler refactoring to share more code between different backends, but I think even after this it would be very big project. And it's not clear why do you need this, you already can run Kotlin on server using JVM, JS and even native, so one more dynamic backend with transpiling that target server only looks not really interesting and valuable