Currently you’re using the date/time picker’s exact value as a constraint in your search. That means only items in your database which were created at the precise same millisecond of the date/time picker’s value will be returned.
When you use a date/time picker to select a date only (without a selected time), its value will be the precise moment (to the nearest millisecond) of midnight (12:00am) in the user’s (who selected the date/time’s value) timezone for the selected day.
So unless there were items created at that same millisecond, nothing will show up in the RG.
I’m not sure exactly what you’re trying to do, but I’m guessing you want to show items created on the same day as the chosen date/time?
In that case you need to search for items that were created on, or after the chosen date/ time, but before the chosen date/time plus 1 day.
The selected date/time picker’s value will refer to 00:00 (in the user’s timezone) on the chosen day, so using 1 constraint of:
Created Date ≥ Date/Time Picker's value and another one of
Created Date < Date/Time Picker's value +(Days):1 should return the results for the selected day.
Alternatively, you could use an advanced filter on the returned results, and use ‘rounding’ to match the created date of items to the value of the date/time picker to the nearest day, but in most cases it will be preferable to apply the search constraints outlined above rather than filtering the results.