Kotlin might possibly be the best language for all around development. Its what a modern version of Java would look like. I worked on it developing Android Apps.
My complaint though is that Kotlin doesn't have a package manager of its own. Gradle is very heavy for basic projects. After working with pub, npm and cargo Gradle seems way too much. Hope JetBrains support this. Plus Kotlin support for Vim is pretty dull. Without Vim its hard to shift to Kotlin. I don't want to download another 1 GB, resource crunching IDE on my old laptop.