There are actually a handful of great libraries to help with RL/LLM agents in Pokemon Showdown.
I did a solo hackathon project [0] using poke-env[1] and found it to be pretty easy to get started with. Hoping for an easy-to-use API with this as well.
[0] https://x.com/ditzikow/status/1922004651790000521 [1] https://github.com/hsahovic/poke-env