Learning Erlang isn’t something you need to do from the very beginning. In fact in my personal opinion the best way to put it off is to learn Elixir via Elixir In Action 2e because in a very subtle way you are being prepared for the necessary aspects of the Erlang mindset.
I would also say that Erlang is easier to learn than Elixir provided you can get passed the ant turd tokens. Elixir adds value on top of that through hygienic macros.
Though my personal bias is that I have never been fond of Ruby’s syntax. In fact for people coming from Ruby it can be a bit of a familiarity trap.
A good free resource for learning Erlang is Learn You Some Erlang (it’s good even if you pay for it).
Also
is one of the best architectural books about the BEAM and OTP ecosystem
