Just use NATO Standardization Agreement 1059. The date in question is written as 10MAY25 using this NATO standard. This of course is assuming human-to-human communication. For machine-to-machine communication then you would use RFC 3339 which is a profile of ISO 8601.
theamk•1h ago
If I have to put a date in the document, it's always in the 20xx-05-10 format. No one has been complaining that they could not understand it yet
(and I've just checked in https://en.wikipedia.org/wiki/List_of_date_formats_by_countr... - only one region used yyyy-d-mm format, but even then it is not used "causally". Which means that format as close to unambiguous as one can get.)