As a daily user of Elixir since 2016, having come from a Python/Django background, I can assure you that you can know very little about OTP/Beam and still be immensely productive. But once you learn the underlying concepts that gird Elixir, so many solutions that normally require queues/caching/back pressure/state machines/distributive architectures are all possible with Elixir itself. I can say this honestly that Elixir is the most powerful I’ve ever felt as an engineer in any language.