Is there a way to setTitle on a UIButton that updates all UIControlStates at once?

According to the documentation you should only need to call:

In Objective-C:

[myButton setTitle:@"Play" forState:UIControlStateNormal];

In Swift:

myButton.setTitle("Play", for: .normal)

The UIButton docs explain why:

In general, if a property is not specified for a state, the default is to use the UIControlStateNormal value. If the value for UIControlStateNormal is not set, then the property defaults to a system value. Therefore, at a minimum, you should set the value for the normal state.

Namely, that if you only set the normal value the other states will refer to it when being set.

or you can setTitle by :

[myButton setTitle:@"Play" forState:UIControlStateNormal|UIControlStateHighlighted|UIControlStateSelected];