Since Minecraft 26.1, Mojang moved the "Allow Cheats" option from a one-time world-creation setting into a pause-menu toggle that can be flipped at any time (only Hardcore mode locks it). This breaks the pure survival experience — a single misclick can enable cheats.
This Fabric mod locks that toggle so it can no longer be turned on after the world is created, restoring the classic 1.20.1 behavior.
