I solved these in Elixir with Livebook which is like Jupyter notebooks for Elixir. It's a nice easy way to try out Elixir as you can run it on fly.io's free tier. One thing to be careful of when using Livebook is the code outside of Modules is interpreted and runs slower. So if your solution is running too slow then move most of the work into a Module.
I used this advent of code to learn some Elixir, so my solutions aren't necessarily idiomatic, though I think I solved some problems elegantly and some kind of messy. After solving a problem I like to look over everyone else's solutions in the same language and often learn about some useful functions in the standard library or more idiomatic ways of expressing things, maybe others will like to look over mine.