even things like scala or kotlin?

I'm not in that industry, but in general yes, even other JVM languages, since one of the reasons is that using a common language makes it simpler to move people between projects. If there is a sole kotlin developer or small group of kotlin devs and they leave it's harder to replace. Also integrating new members coming frommother teams is harder. The more architectures, libraries, coding styles, ... are standardized the higher are the chances that others can take over which is beneficial even if individual productivity might be lower.