Have you tried Elixir? I see mention of other programming languages but when it comes to distributed programming or scalability, Elixir (or Erlang, but you may not like the syntax) is suitable.
When it comes to projects requiring scalability, to me, Go is for smaller or toy projects, Elixir is for more serious ones. That said, I have written some more serious stuff in Go. I like the language, too. I can get really productive in it easily.
Elixir makes a lot of sense if you're from an Erlang or Ruby background. Syntactically, I'm not a fan as I come from a C background.
One consideration I have is that Go is straightforward to hire for. You can hire good engineers from any background, and they can pick up the language quickly. I'm not sure you'd get the same instant hit to productivity with Elixir.
When it comes to projects requiring scalability, to me, Go is for smaller or toy projects, Elixir is for more serious ones. That said, I have written some more serious stuff in Go. I like the language, too. I can get really productive in it easily.