So basically, you can toggle cheats off for a world (hardcore defaults enable it) and you can't cheat. But you can host a single-player world to LAN, and while you do that, you can enable cheats in the hosting options. So I have noticed, while playing on hardcore which doesn't allow people to cheat, you can use commands after hosting to LAN. This also applies to worlds you disabled "allow cheats" in creating world options. And this applies to most versions but I clicked 1.20.4 cuz it requested a version