It's a very simple language. I've worked on half a dozen projects where I helped an experienced dev new to Elixir ramp up to 80%-90% productivity within a few days.
Learning Phoenix (and a few other libraries like Ecto and now LiveView) is what would eat up your time.
Phoenix used to be very easy for Rails/Django/Laravel devs to pick up a few years ago, but now that LiveView is thoroughly built-in and Phoenix.View has been replaced by Phoenix.Component, it's much less familiar to those learners.
Learning Phoenix (and a few other libraries like Ecto and now LiveView) is what would eat up your time.
Phoenix used to be very easy for Rails/Django/Laravel devs to pick up a few years ago, but now that LiveView is thoroughly built-in and Phoenix.View has been replaced by Phoenix.Component, it's much less familiar to those learners.