Speaking as someone more into Elixir than Erlang, I'm wondering why you want to move to Elixir at all? If you're happier in Erlang, then why not stick with that? For me, the best thing about Elixir is the BEAM, and you've obviously already got that. If you don't want or need metaprogramming, or the various Elixir conveniences feel less than convenient to you, it seems like you may as stick with what you find comfortable.
If you don't enjoy writing Elixir, you could always just install Elixir, and then write Erlang that calls into Elixir-stdlib modules.
I believe you can even install Elixir packages into an Erlang rebar project, if you like. No need for Mix or anything.