I’ve never read comments, articles, books in LLM’s current style before LLMs, and somehow, since then, I read comments like these every other day. This phenomenon is way overblown at the minimum. And since nobody showed a counter example from before 2022 which can be confused as LLM generated (using em dashes was never in it self that) I tend to say that it never even existed.

You can use em dashes as long as you don't write like a bot.