Please explain!
Well, this is probably not the place to start a theological war. But I can tell you that as we near the end you will see Sundays exalted more and more for a variety of reasons. From Climate change to catastrophic events and social breakdown. The world will turn to the church for help.
I have found it interesting that Christmas is always December 25, but Easter is always Sunday but a very moveable date in March or April with long calculations to get it to match Passover.