Those languages have different syntaxes and platforms but are almost all the same thing (inheritance-based OO imperative programming). Because you've basically learnt the same language over and over again, you haven't progressed. But there is a cure...
> I just feel guilty that I haven’t done anything with Erlang, Clojure, Rust, Go, C#, Scala, Haskell, Julia, Scheme, Swift, or OCaml
Unlike the list of languages you've used, this list actually has more variety of paradigms so learning many of these will cure you:
Erlang, Go - communicating processes
Clojure, Scheme, Julia - user-defined macros
Scala, Haskell, OCaml - functional paradigm
Haskell, Clojure - immutability