Hi Hannah,
This is an interesting observation.
There are two similar but different pages, but there is no way to change which one is used in the link
calendar/view.php?view=month
calendar/view.php?view=upcoming&course=1
Having alternative options to choose from would be a good idea for an improvement to this block. If you've not already done so, you can do this by navigating to our Totara ideas tool.
Tom