yyyy-MM-dd HH:mm works best for me, stored in a text field so it doesn't get converted to that ungodly float-since-1899 format and rendered by reference via =TE

yyyy-MM-dd HH:mm works best for me, stored in a text field so it doesn't get converted to that ungodly float-since-1899 format and rendered by reference via =TEXT but can still be sorted and compared alphabetically it is unforgivable that a program used for timeseries data can't interpret an ISO 8901 without third party macros