To be clear, i'm not claiming that you take an LLM and do some RL on it and suddenly it can do particular tasks. I'm saying that if you train it from scratch using RL it will be able to do certain well defined formal tasks.
Idk what you mean about the online learning ability tbh. The paper uses it in the exact way you specify, which is that it uses RL to play montezuma's revenge and gets better on the fly.
Similar to my point about the inference time RL ability of the alphaProof LLM. That's why I emphasized that RL is done at inference time, like each proof you do it uses to make itself better for next time.
I think you are taking LLM to mean GPT style models, and I am taking LLM to mean transformers which output text, and they can be trained to do any variety of things.