LocalLlama is the place. Really high quality people and discussion there and surprisingly collaborative. Very different than most subreddits.

I like LocalLLaMA because it's not just for algorithm/math experts, it's for people who want to use LLMs locally (as the name says), so there is often practical discussion on how to use "off the shelf" models and kits. This also implies a patient crowd who will sometimes go into great detail about specific details, since there are many non-specialists.