kotlin is nice for backend development if you're using quarkus or springboot.

don't use ktor etc where some people wanna take their scala religion and put into kotlin.

kotlin is nice is you keep is super simple. use it the same way as you do Golang and you will find it pleasurable.

i've used ktor for 2 small-ish microservices. It's fine. I was curious about corouitnes. I know SpringBoot has support for corouitnes as well, but in ktor it's front and center. (Disclaimer: I never used Scala)