Jun 23 2022 07:47 AM
I'm guessing at one possible meaning behind your question. You'll find that solution in the attached spreadsheet. If that's not what you had in mind, please come back with a more complete description.
This one assumes that you have in minds some sort of monthly deadlines, or monthly meetings....and those dates are known.... So the drop down goes from a list of those known dates. It looks like this:
Jun 23 2022 07:49 AM
Jun 23 2022 08:07 AM
Jun 23 2022 08:11 AM
Jun 23 2022 08:23 AM
IF you are working in fact with a limited set of dates, say for the next two months, and workdays only (or weekends only)...I've created a fancier version of the drop down that includes the day of the week as well as the date. It now looks like this: