Custom Trailing Date Issue in Power BI

Hi, I have 2 columns consisting of random dates “start date” and “end date”, ( trailing date) as below, and we want to put this in any BI tools available out there. Thus, we want to count and sum and do some calculation between those 2 dates, Please advise on how to do this, I have been stuck with this problem for so long. Refer below table for reference.