I've done some stuff in Node, Python, Java, Scala, R, TypeScript and some other stuff I'm sure, as well. But every time I'm on a project like that I just slog through, constantly reminded of what I'm missing. At this point I'm sure it's something like a "lingua franca" effect, but the point remains that I pine for comfy C# when I'm not using it.

I will say I did quite like working with Scala the language, despite the rather uncomfy Java ecosystem/tooling. Probably the only direction I'd want to go to leave C#/.NET as my primary tools would be towards Scala/F#/Haskell/Clojure/Erlang, etc. but the market for those is comparatively tiny.