Try the quotation dash (U+2015), sometimes called the horizontal bar. Unlike the em-dash (U+2014) it hasn't been hijacked by AI.

I sometimes comment on Hacker News to study English, and then get AI help with spelling and grammar. When it edits my writing, it tends to add em-dash, so I assumed that was just natural. (I also picked up the tendency to think of English with em-dash as "formal English.")

So in the past, em-dash were evidence of an formal English user, but now people say they're evidence of AI. In the end, whether it's language or anything else, the evaluation seems to depend on who the user group is.