How do I unhide pages of apps on iphone 13

At the bottom of any home screen there is a search button. Press and hold that until all of the apps start wiggling then let off of it. Right where you just pressed and held, it is now a bunch of dots, click it.

All of your home screens are shown on the screen. Make sure that they are all check marked.

My guess is that the missing page of apps isn't check marked.

For more information, use this link and then scroll down to "Hide and show Home Screen pages"

Find your apps in App Library on iPhone - Apple Support