All I want is apply these languages into the prime purposes it was designed for, but on one condition that I can choose only one - either Dart or Go, after careful evaluation of languages out there.
I am not learning for career and big projects perspective. I have some small projects in mind mostly around web development.
Just look at different world: Clojure, Haskell, Ocaml, Erlang (maybe Elixir). Even Smalltalk shows you true priciples of OOP which are far from Java/C++ and close to Erlang processes/actors.
These languages force you to think different.
BTW, Elixir can really help you in Web projects because it has Phoenix LiveView framework.
Seaside framework for Pharo (Smalltalk) is very nice as well.