Andrej and Garry Trudeau are in agreement that "blue book exams" (I.e. the teacher gives you a blank exam booklet, traditionally blue) to fill out in person for the test, after confiscating devices, is the only way to assess students anymore.
My 7 year old hasn't figured out how to use any LLMs yet, but I'm sure the day will come very soon. I hope his school district is prepared. They recently instituted a district-wide "no phones" policy, which is a good first step.