I recommend learning Elm to pretty much every front-end developer. It's great that FP-style patterns in JavaScript have become more popular, and I'm absolutely thrilled that Redux has played a part in it, but there's only so much FP you can do in JS given the limitations of a language. Elm is an ML-style, purely functional language, so you'll get to learn things like pattern matching, algebraic types, and "immutability everywhere" that aren't possible with JavaScript.
Whether you learn Redux or Elm first probably varies from person to person. Dan and I both didn't really understand Elm until after we had created Redux and "accidentally" (subconsciously?) borrowed some of its ideas. We've heard from other people who report the same. So if learning Elm is overwhelming, give Redux a try and go back to Elm later to get the full experience.