But really what's most important is learning portable skills, which amounts to learning about different approaches. In that case, I'd say learn both.
There are a lot of interesting ideas in both languages.
(I learned a lot of great ideas from Go, especially about concurrency. I think it's great for writing the kind of frameworks where that matters. But in terms of "normal" business logic programming, I think it's trash. It not ergonomic at all.)
What's your background? I've mainly used language with huge standard libraries and Go's intentionally small standard library feels very unergonomic sometimes (I miss sets).
Elixir feels very ergonomic to me, but a lot of programmers struggle with the lack of typing.