Having tried a few different strategies, now, before moving along, I can say with confidence now that an LLM might be useful for juicing you up on your writing if you're feeling imposter syndrome-y about it, that's really about the extent of its capabilities. It can be good to like, hint you at a certain part of your manuscript that may need work, but I really question the people who say that it's a replacement for a real editor. If I'd taken even 50% of the advice this thing gave me, my book would be trash.
I do now just really need a few actual human beta-readers. You don't have to be a writer (in fact, it's better if you aren't). You don't even have to like me as a person (also better if you don't). You don't even have to know me, just like...be someone who likes literary fantasy and can boot through a 200 page novel.