Hey just wanted to respond to this for anyone else who is looking for help.
I can confirm on {:argon2_elixir, "~> 2.0"} (currently at 2.4 as of this post)
Putting the following in runtime.exs and deploying to fly.io w/ lowest plan works smoothly.
config :argon2_elixir, t_cost: 4, m_cost: 16
Thank you @brainlid !
