Earlier quoted context omitted.
This is a lot more wide-spread than "some kids on Reddit". Maybe 30% of the kids in my son's class are using this or related tools.
Any ideas on how to solve this issue of kids cheating with GPT3 essays?
The highest-quality answer involves skilled teachers with enough time who know and understand their students. (Actually the very highest might involve personal tutors but let's leave that aside.)
Going down a few steps you might combine the automated approach with skilled teachers and maybe add human editors who can do support work asynchronously?