Welcome to the community!!
I think I just have what you are looking for
So here, you wish to click on days which are working days and you need to find a way to omit the holidays between those days right?
Check out this custom activity
This includes an activity named Custom Date Series
This activity will generate a list of dates based on your configuration of holiday and working day.
If you can use this activity to get the working days, your task of selecting the date here in the date time picker would be very much easier as you don’t need to worry about omitting holidays.
Check the user guide attached to the activity set and give the date pattern as required for your requirement. It will give you a list of all the dates you require omitting the unwanted