How can we improve WHMCS?

In WHMCS Admin Area - Product Service currently, when we open the calendar in of next due date it automatically shows today's date.

It is very confusing because when we have to change the due date of the client 2 days ahead of the next due date, we end up setting 2 days from today. I'm sure this happens with most of the users.
This is a bad UX design to show different dates on the text box and on the popup calendar. Check the attached screenshot.

Current Scenario
WHMCS Highlights the current date in Blue Box

Suggested
Highlight Current date with a white box and blue border, and show the selected date in Solid Blue Box.

To give a practical scenario :
Suppose today is the 15th of Jan 2022 and the next due date of my client is the 25th of Feb 2022.

Now, if I want to add 3 days to the client, I'll click on the next due date field and it will automatically open the calendar of Jan 2022 and not Feb 2022. Why? It doesn't make sense.