I am a bit of an LLM cynic but I am trying to learn it all, and I have to say I have spent most time trying to work out: how do you explain how a brown-field codebase actually works, in such a way that the LLM won't pervert it through misunderstanding.
It does encourage you towards the "conventional" coding standard for any new project, because you want to use a pattern that it will have seen in its training set.
But for example there are differences of opinion in how wordpress plugins (which have a very complex control flow) should be structured. LLMs are incredible at knowing how WP works, actually, but what is difficult is explaining how your methodology for a large plugin is going to work.
It is a battle — but a useful one because it can be used for, er, studying the comparative belief systems of the LLMs.