At this point when you are in the process of creating a hardcore world, cheats are automatically turned off and CANNOT be turned back on, however when you spawn in you can simply open to lan and turn cheats on making it so that you can switch from survival to creative, this also allows you to come back to life because you can go into spectator on death and then you can go back into creative mode after dying you can also go back into survival after dying in a world where you are supposedly not able to respawn. this literally makes it pointless to have cheats automatically turned off because you can just turn them on whenever you want even if you have them disabled on world creation. There should be a setting to permanently turn cheats off and make it impossible to turn them back on again that way hardcore is ACTUALY hardcore not just normal survival on hard difficulty.