7 month ago received an offer to join Scala project. Before that worked with Java and Go. I would say Scala is an amazing not just language, but an ecosystem. As a language, it’s very ergonomic and allows to do complex things with less boilerplate. So if you really interested in programming, learning new concepts - I would recommend to try it. If you want just to do boring stuff for money - Java and Golang. Regarding Kotlin - it doesn’t intersect with Scala, because mostly used for Android and back-end with Spring or other Java frameworks. Scala is mostly used for distributed systems, big data and applications with complex domain.