The Shift Page shortcuts are not coming from the keyboard shortcuts panel. When I try to enter them says ai cannot use that, searching with artboard was no help either. Tried making an action, btu unfortuantley that did nto work either. I also chcked the system Preference for Keybaord, and could nto find the keyboard shorcut coming fomr there either.
In summary uopu can use home and end while inside text and the I beam is flashing, btu not page up or page down. That seems to be a hidden comand for goingf to next and previous artboard, so that will lwork without any text on the page.