I'm not sure it's about courage, a lot of it I imagine will relate to preferences and beliefs (and what players you have).
I think we'd all say that Nuno's preferences and framework served us pretty well, as the most successful manager in most of our supporting lifetimes!
You'd think that concentrating on fewer changes in formation and approach would lead to greater understanding and expertise in the ones you do prioritise, and at the other extreme, tinkering around constantly could result in a shallow understanding largely untested in game situations.
As with everything, a high quality manager will get it right more often than not