Asgorath
Explorer
And if the attack action is made up of N discrete elements then it must have a duration...
In other words changing your claim to the attack action being made up of N discrete elements logically implies that it has a duration which contradicts your original premise that actions have no duration.
As I've said, your turn is made up of discrete elements in an ordered list. Duration has no relevance. There's an explicit rule that says your Attack action can be split by movement. There are also bonus actions that are triggered by a single attack in the Attack action. Why do you insist on applying a duration to any of this? It simply has no bearing on the order of the elements in your turn.