I can't help but immediately think about a counteracting piece of software, which asks an LLM for variations of a paragraph, or a phrase, or a few synonyms, and types it the way a human would, with pauses, typos, navigation, rearranging pieces via copy-paste, etc.

Not that your software is going to be useless. But as long as there is an incentive to cheat, new and better tools that facilitate cheating will crop up. Something else should change.