They're not just from AI-generated text. Some of us humans use en dashes and em dashes in the right context, since they're easy to type on macOS: alt+hyphen and alt+shift+hyphen respectively.
On both iOS and modern Android I believe you can access them with a long press on hyphen.
They have their place but I'm really just trying to avoid the AI house style that has emerged. I'd rather have my writing—AI-assisted or not—reflect how I actually communicate rather than defaulting to patterns that have become over represented in generated text.
On both iOS and modern Android I believe you can access them with a long press on hyphen.