As for Scala it's pretty much a dead language, no one work with it and it's impossible to find dev for it.
10 years ago I was moving Scala code back to regular Java.
go and kotlin aren't it, gleam scratches the itch but I can't justify writing code that would impossible to hire for.
scala situation is a real shame.
I think it used to be common to just look for smart people and assume they can run with whatever stack. Wasn't that the point of abstract algorithm questions etc. (basically an IQ test)?
Lots of companies where software isn't the focus see it as a cost center, so they'd prefer to hire lower-IQ specialists instead of higher-IQ generalists, because the latter are more expensive/have more options.
I worked on a purely functional Scala codebase (Cats). I joined after the original authors were gone.
Some new comers were not fluent in it after ~a year.