Good job. I don't give out compliments often but you deserve this.

Instead of Erlang, might I suggest Elixir? It's still based on BEAM but it has a much nicer syntax.

Personally, I would go with Smalltalk (perhaps VAST or Pharo). It's a much nicer language in many ways. Read https://itnext.io/mmxxii-year-long-celebrations-for-smalltalk-e56bf8d6733b.