So write YYYY-MM-DD!
But also, the most sacret of all days has been honored by the one day of the year "said properly" fourth of july!
Changing formats is just asking for a large event on 9 November.
No native speaker but isn't 4th of July more common than July 4th?
You could even say "The Fourth" and almost all Americans would understand. I think that's why; [begin speculation] it's such an exceptional date it necessitates saying it differently.
The Fourth of July and Cinco de Mayo are exceptional days.
Tax day is the ides of April, but we just say April 15th.
But people are very good at verbally saying different than is written.