This is something that I have found LLMs nearly completely useless for. I gave a talk on uses of AI for gamedev, and had some great things but I couldn't get it to write a blurb for the talk that wasn't vomit inducing.
This isn't so much a problem white LLMs themselves but the training data. The world is so inundated with meaningless marketing speak that when you try and get it to talk about a topic in even a slightly promotional manner it will create something that fits in nicely with the existing drivel.
I have the same problem writing references for students and summarising my feedback to them. I find asking to “write concisely and without waffle, like a brusque, British academic” helps a bit.
This isn't so much a problem white LLMs themselves but the training data. The world is so inundated with meaningless marketing speak that when you try and get it to talk about a topic in even a slightly promotional manner it will create something that fits in nicely with the existing drivel.