The bolded bit is where is shows me just how little you know about the GFA.
Ultimately there will be a fudge, kick the can down the road, then the North will vote on it in 2024. Potentially there could be a stark choice to be made by all parties if they vote to scrap it. The EU will have then no choice but to but a border in Ireland because they couldn't, and never have given two shits about peace on Ireland. The single market is sacrosanct, and any price paid in blood is a price worth paying