I had my cheats turned on in my world, even after when the world was downloaded from the realm, it won't do well. I tried doing /setmaxplayers command on Bedrock when cheats were turned on, it then keeps saying "Unknown Command". I dont know if that command needs permission when I'm the owner of the world or if it did exist or not. I was using /setmaxplayers 12 on a command that had cheats on as always, but it looked like the same issue here anyways. It also had a problem that /setmaxplayers was not there in my command list with cheats turned on, even with /op and /deop. Although, /op and /deop does not exist in the downloaded world from realms. The world I downloaded from the realm does not match the other worlds I own in world settings. Some downloaded worlds only matched with realm settings I own.