Check JWT calculated date-time fields to learn the steps on how to add a calculated date-time field.
Create a new Calculated Date-Time Field custom field called "Predicted due date of an epic"
Parser expression
Add the following expression:
addTimeSkippingWeekends({00057}, {10200}*{DAY}, LOCAL, {FRIDAY}, {SATURDAY}
Click on Edit Display Format to configure the display format
Choose Date Time Picker for Format type
Once configured and added to an issue screen (e.g. an epic), the result will look like this:
