Hello,
I'm not sure I understand the purpose of the user input (scheduling?). But if you have to have the user input for the user to enter a day and time than three possible options you could look at include:
1. The javascript action. You could probably convert the user input value to a date object and then do the comparison.
2. The Run Command Line action (to run on linux) to do the conversion and comparison.
3. Powershell action to do the conversion and comparison.
If you are bound to the user input to get a date and time then I would recommend you use another action to confirm that the format is what you were expecting and that the values are valid. For example, a value of 13 for the month wouldn't be valid and, if you're lucky, would fail in later conversions.
Kind regards,
Gregg