I did Ruby on rails professionally for many years, and have also done elix Phoenix professionally for many years now, and I would advise you to continue with Phoenix. Getting really good at elixir and Phoenix can make you an extremely powerful and employable developer. Should you find yourself in a situation where you need to switch to Ruby and rails, you will have a huge leg up because rails follow as many of the same patterns as Phoenix, and the Ruby language is very simple to learn for someone coming from elixir. Just my two cents of course