When I tried to increase the amount of players allowed on my world, the setmaxplayers command was not available without cheats on. 

steps to reproduce

1: open a new world with cheats off on bedrock 

2: open chat and type /setmaxplayers and set the number to a value

3: you will get back an error saying that cheats are not on on this world

It does not work without cheats on, but it should be there as my world has lots of people wanting to be on it